In his earliest incarnation, Superman held a job at The Daily Planet so he would be the first to hear about misdeeds he could set right. As the character developed Super-Senses, the need for him to learn about such things from the Planet was obviated; however, the job is such a central part of the mythos that it has continued into every Continuity Reboot and adaptation to date. In 1971's Kryptonite Nevermore, writer Denny O'Neil actually did do away with the job at the Planet, with Clark taking the more modern job as a news anchor on a national station, but it was eventually changed back Post-Crisis to tie in with the Superman movies, which featured Clark at the Planet with his classic supporting cast. It's been justified as Clark having been interested in journalism even before he became Superman, or journalism being a career where he can succeed in a purely intellectual field where his powers give him no real advantage over ordinary people, and where he's justified in running off as soon as reports of some sort of emergency start coming in.
In The Silver Age of Comic Books Superman had a lot of spin-off characters like Supergirl and Krypto the Superdog, and odd powers like Super-ventriloquism. Throughout the Bronze Age Superman's derivative characters, weird powers, and even aspects of the lore such like the Phantom Zone, Bizarro World and the different colors of Kryptonite became perceived as severely outdated, which led to their removal when Superman was rebooted in 1986. Nonetheless, DC spent the whole Dark Age trying and failing to replace them adequately, and after one decade and half they were again regarded as fresh and valuable additions, so they were reintroduced.
Superman's superhero attire was inspired in The '30s by the then-current suit of a circus strongman. The leotards, the trunks over them... even the cape, which the strongman would wear but remove right before performing his feats. With circuses fading increasingly into the past, the reference is not so clear.
Similarly, Supergirl wears a skirt because the costumes of female heroes like Captain Marvel's sister Mary Marvel]] were inspired by female ice-skaters early on. As this influence began fading, skirt-wearing heroines became increasingly uncommon, but Supergirl goes on wearing one because it's become her iconic look.
In 1983 storyline Brainiac Rebirth, Brainiac's skull-shaped starship was modeled after Brainiac's head in his Skele-Bot phase. While Brainiac would go back to his older green-skinned appearance, the design of his ship stuck.
Jonathan Carroll, Lois Lane's boyfriend in Action Comics (New 52) and Superman New 52 rarely had any bearing on the stories and was only there to show that Lois already had a boyfriend, to the point he disappeared for entire story arcs. By the end of the relaunch, it was clear the writers had no idea what to do with him, so they eventually wrote him off altogether.
Steve Trevor was, notionally, Diana's love interest, but from the 50s onward nobody could really get much of a read on him; he was killed off at least twice in the Silver and Bronze ages, and revived both times largely because writers assumed he must have some kind of role in the comics. The 1987 reboot aged him and did away with him as Diana's love interest, marrying him to another character; subsequent debate about the character has revolved around whether or not his old position should be restored, but quite a few fans see no reason to. Completely averted as of the New 52 and DC Rebirth, however, where Trevor has been upgraded to being the DCU's version of Nick Fury.
The '87 reboot itself had its decision to set Wonder Woman's debut in the "current" day, rather than some time in the past. It made sense then; it was meant to be a lengthy ongoing and reinvention that interacted with the other books in the lineup. As time went on, though, it became more troublesome—Wonder Woman is, after all, supposed to be one of the more iconic characters in the DCU, but it's a fair bit harder to sell her as that when she debuted after most of the Teen Titans (hell, by the time she showed up, Batman was on his second Robin), and you couldn't really sell her as a newcomer, either, because the '87 run only became more distant with time. It also ended up creating further problems down the line, because it made Donna Troy's existence impossible, necessitating multiple waves of retcons. Doing away with the idea and just declaring she showed up at around the same time as Superman and Batman was one of the few changes of Infinite Crisis that didn't create much controversy.
Wonder Woman's invisible jet. Contrary to the visual depiction, it does make Wonder Woman invisible as well, but in the modern era, where Wonder Woman can fly on her own like Supermannote In the Golden Age, she could only jump hella high. In the Silver Age, she developed an ability to "glide on air currents"., it can seem kind of pointless. Occasionally justified - e.g., for sneaking up on, and landing on a possessed Power Girl in The Book Of Destiny, or for carrying passengers. (Black Canary once remarked that being carried across an ocean by a flying hero could be really annoying, because your underwear rides up and you can't adjust....)
Her armored corset's iconic stars-and-stripes motif made a lot more sense in the Golden Age comics, when she was persuaded to enter "Man's World" for the first time by an Army officer, she was an Army nurse in her civilian identity, and every other issue involved her fighting the Nazis. note Understandable, considering the series began in December 1941, around the same time that the United States entered World War II. Now that Greek Mythology has become such a central part of the series' lore (with her powers now said to be gifts from the Gods of Olympus) and more time has passed from her World War II incarnation, her decision to wear the American flag on her costume seemed a bit baffling, but her costume's design was far too well-known to change. Some writers gave a halfhearted explanation that she saw herself as an ambassador to the US, and wears their colors as a somewhat odd act of patriotism, though others don't even give her that. At least the eagle was Zeus's symbol, so that motif still fit. However, her original costume was phased out throughout the second half of the 2010s in favor of a more Greek-inspired one that was originally designed by Michael Wilkinson for the film franchise with the stars-and-stripes downplayed heavily and a dark red, blue, and gold color palette rather than flag colors.
Wonder Woman blocking bullets with her bracelets was something that made sense during a classical age when she was less powerful and such a skillset was needed. But over time, Wonder Woman has progressively become more powerful, strong, and durable, to the point where she can fight beings like Superman, Darkseid, Despero, or The Batman Who Laughs. And because of her gradual Power Creep, Power Seep into being DC's World's Strongest Woman, one would think bullets would be like Shooting Superman to Wonder Woman. But even into the modern era, there are some writers who still portray her as being able to suffer cutting or piercing damage and still needing to block bullets with her bracelet, even though it's difficult to swallow that the same superheroine who once got punched by an unrestrained Superman from the sun all the way back to Earth while surviving re-entry can be killed by a simple bullet to the head. However, because Wonder Woman blocking bullets with her bracelets is such an iconic trademark move of her character, it's been kept even into the modern age despite the incongruence of a superheroine who's essentially a Flying Brick being susceptible to being injured or conceivably killed by bullets.
The Legion of Super-Heroes has a group called the Legion of Super-Villains. This sort of Silver Age name would never be used nowadays (since nobody thinks of themselves as villains), but is so closely associated with the group that it can't be changed in the comic. (The cartoon used Light Speed Vanguard.)
Poison Ivy falls into this from two angles. When she was introduced, she was a fairly classical Femme Fatale archetype with a mild plant theme and a fondness for poison. The idea of Batman falling for her wiles made some sense when he'd spent the last decade desperately trying to prove his heterosexuality and getting into Ship Tease situations with Batwoman, so she slotted in pretty easily. She got a Retool by Neil Gaiman in the 80s, adding explicit superpowers and plant-based abilities to her repertoire, meant at the time to utilize the lore of the popular Swamp Thing and make her a bit more interesting (especially in an era where Batman villains with strange supernatural powers were quite common). But in the years to follow, Batman villains overwhelmingly shifted in the direction of being more low-key and "realistic", and Batman himself developed into an increasingly stoic and sexless sort outside of maybe Catwoman. This led to Ivy feeling very out-of-place, with her overt supernatural powers that are miles away from any kind of realistic science and focus on trying to seduce and manipulate a guy defined in part by absurd mental fortitude and no interest in romance (aside from the datedness of a femme fatale in general). It's likely for this reason that you're much more likely to find her with Harley Quinn than with Batman in a modern comic.
Two-Face came from an era where most Batman villains were little more than gangsters with gimmicks, and Batman's abilities weren't much greater than those of, say, Dick Tracy. As the stories grew Darker and Edgier and Hollywood Psych became a theme, he was given a further twist of his duality representing a Split Personality, and having a personal connection to Batman, which solidified him as a big player. However, throughout all this time, his capabilities remained largely static, even as those of Batman and the other iconic rogues started to creep upward. Modern Two-Face doesn't have any powers to fight Batman, he isn't an overt Badass Normal that can match Batman in hand-to-hand, he isn't a supergenius, he doesn't use any piece of technology, magical artifact, or other paraphernalia that could give him an advantage, he's rarely depicted as anything more than a middle-ranking crime boss (The Don usually tends to be the Penguin or Black Mask), he doesn't command a particularly imposing army like the League of Assassins or the 99 Fiends, he isn't insanely rich, he isn't a Villain with Good Publicity or anything like that (he used to be a prominent lawyer, but lost all of that from the tragic accident that turned him into a supervillain) and he isn't the type of villain to have powerful allies like the Legion of Doom or the Secret Society of Supervillains (he isn't even that big of a team player inside Gotham City). His only niche is being tied to Batman's past and demonstrating how the struggles of a good man to clean up Gotham can sometimes fail, and even much of that niche is confined to his origin story. Yet despite all this, comics like Batman: The Long Halloween and movies like The Dark Knight or Batman Forever mean he's too iconic to be anything less than an A-lister, despite the great power imbalance existing between him and Batman.
The manga series Batman: Justice Buster seems to directly lampshade this when Two-Face makes his appearance. Batman has always kept up with the times in terms of technology but this series sees Batman sporting more high tech armor and a highly advanced Batmobile that can also transform into a Humongous Mecha. Once Two-Face makes his appearance, he's still sporting his usual mobster suit, is driving away in a normal getaway car for gangsters, wields a classical tommy gun, and is doing a classic attempted mob hit job on someone he was paid to kill. Inevitably, the outcome was that the Batmobile took out Two-Face's getaway car in one shot and after that, Batman drags Two-Face out and starts grilling him. Additionally, when Two-Face was in his getaway car, Batman was even having a chat with Alfred about the need to keep up with technology's advance.
For decades Swamp Thing's quest to become human again was this. It was a Series Goal that couldn't be resolved without ending the series, so Swamp Thing always spent at least part of his time trying and failing to find a cure simply because that was part of his gimmick. Part of the reason Alan Moore's run is so acclaimed is that he saw how much of a useless load the "search for a cure" idea had become and retconned it away with a vengeance by having Swamp Thing discover that he was never actually Alec Holland to begin with, finally ending its Artifact status.
Nightwing is one of the few characters in fiction who is still allowed to be called "Dick" unironically. It was a perfectly normal shortening for "Richard" in the 1940s but with time the meaning has evolved. In modern times you're more likely to hear a Richard be called "Rick/Ricky", "Rich/Richie", or just "Richard" than "Dick". Even Nightwing has had a few jokes poked at his name, such as Beast Boy (whose name "Garfield" is treated like an Embarrassing First Name due to a certain cat) finding it weird in the Young Justice (2010) cartoon.
While not quite as silly as Nightwing, the real name of Batman villain Clayface is Basil Karlo. In the 1940s, the name was already a bit dated, and this was likely by design, as his origin depicted him as a somewhat older man. Nowadays, the name has only gotten less popular, and the gap between now and its peak has grown many times over.
This has increasingly come to apply to Tim Drake. He was introduced as a Reconstruction of the Robin concept after Jason Todd's death. He immediately became the Deuteragonist of the franchise, had his own supporting cast and book, and he remains very popular. However, Damian Wayne became the new Robin during Batman (Grant Morrison), leaving Tim in an odd place. Dick Grayson better fills the role of Kid Hero All Grown-Up and is usually billed as Bruce's successor, while Barbara Gordon is a Badass Bookworm who fought on her own initiative—both roles that Tim used to have. Jason Todd went bad, so he stands out. Meanwhile, Identity Crisis (2004) removed several more of Tim's unique points (having a non-adopted family and a genuine longstanding romance). In recent years Tim is usually on a team book or Put on a Bus, and when interacting with the rest of the Bat-Family he's often written as The Generic Guy (or The Smart Guy, but that feels generic in a cast with so many geniuses). Even his codename is up in the air: is he Red Robin, Drake or just "the Robin other than Damian?". Tim coming out as bisexual in the 2020s may have been an attempt to give him something to help him stand out once more, but as he is not the Bat-Family's first LGBT member (Batwoman was reintroduced as a lesbian in the 2000s), this only serves to at least help him stick out among the various other Robins.
Though Robin is not quite the only Sidekick left in the DCU, it certainly feels like it at times. While the concept was popular in the 40s and through the 60s, the idea has become less-so over time as a negative stigma of the title grew from both readers and subsequently in-universe. Many other sidekicks such as Speedy and Wonder Girl have become independent heroes or team members (often with a new accompanying name), and though new sidekicks occasionally get rotated in, they rarely attain the prominence and omnipresence that they once held. Even the identity's Distaff CounterpartBatgirl has operated independently for a very long time, and the title is no longer a "sidekick" to Batman. It's also admittedly out of character for someone like Batman, known as The Dark Knight, who explicitly works alone in many cases, to take in a teenager, dress them up in a bright red costume, and have them fight crime alongside him. But Robin is such a core part of the Batman mythos that it's impossible to imagine Batman without him. There have been attempts to justify it, by having him balance out Batman's inner darkness or by having Batman take in a troubled child, but it still looks rather out-of-place in the overall mythos of both Batman and the large scale DCU.
The Dan DiDio era infamously did this to a lot of Legacy Characters active in DC, especially those introduced in the 90s: reintroducing their old mentors and handing the mantle back up, introducing a new character and having the mantle passed down to them, or both. This left characters like Conner Kent, Cassandra Cain, Wally West, Kyle Rayner, and, as mentioned above, Tim Drake, without any clear purpose: still popular and beloved, but unable to fill the big-ticket starring roles they were designed to carry. A lot of them putter around B-tier books trying to get a new identity to stick.
Black Canary's famous costume with the fishnets is an artifact from her original role. The first Black Canary started out as a Femme Fatale-esque thief in a detective comic. When she became a less villainous character and became a superhero, the costume stuck. While there have been attempts to change it, the fishnet costume is the most popular and is always eventually brought back in some form.
Barry Allen's costume ring. At the time, it was a cool and convenient way for Barry to store his costume out of sight. However, his successor, Wally West, eventually just started to manifest a costume using the Speed Force. In-universe, Barry himself eventually learned this trick from Wally off-screen, but still uses the ring, which Wally laments. In the New 52, Barry's suit is segmented armour, which might explain things... but that's Depending on the Artist (many artists draw it without it being metal) and the armour itself is no more durable than any other superhero costume — in fact, it's shredded more often than any other Flash's suit.
The Flashes having secret identities. Originally, it was because it was standard superhero stuff at the time. However, after Barry Allen's (Flash II) death, Wally West (Flash III) operated as the Flash alongside Jay Garrick (Flash I), and neither had a secret identity. This was the case for almost all of Wally's career as the Flash, until an attack on his wife Linda by Hunter Zolomon (Reverse-Flash II) caused him to accidentally request that Hal Jordan (then the Spectre) to erase knowledge of the Flashes' identities from the world, and when he discovers this, Wally decides to keep his and Barry's identities secret... except Hunter retained this knowledge. As did the previous Reverse-Flash, Eobard Thawne, who killed Iris West, Barry's wife. And every other Flash villain who would go after the Flashes' loved ones either regained this knowledge (Abra Kadabra) or already knows (Hot Pursuit, Future Flash, Grodd, Negative Flash), while the Rogues actively don't go after the Flashes' loves ones, even when they did know. So the few people they need to keep their identities from already know, and those who don't anymore never used this knowledge anyway.
When writing The Multiversity, Grant Morrison intended Earth-31 to be the world of Frank Miller's various stories, such as The Dark Knight Returns, as it was in the pre-Flashpoint days. However, Miller claimed he didn't want his world to get wrapped up in multiversal antics, and so out of respect, Morrison changed Earth-31 to be an Ocean Punk world where most superheroes are pirates. However, this happened too late to change the design of Earth-31 on the multiverse map, which gives it a scratchy, inky, black-and-white look that clearly invokes Miller's style, and positioned it opposite of Earth-25, the world of America's Best Comics (which would make an awful lot of sense as an opposite to a grim-and-gritty world created by Miller, being a Reconstruction spearheaded by Alan Moore).
In the late 1980s, as part of a general attempt to retool Batman into his modern identity, he was stated to be a fairly extreme loner with few major allies outside of Alfred and Commissioner Gordon, taking cues from works like Batman (1989), the very earliest Finger/Kane stories, Batman: Year One, and the first half of The Dark Knight Returns. This was aided by events like A Death in the Family and The Killing Joke that picked off major parts of his supporting cast, his absence from team books past the early arcs of Justice League International, and Dick Grayson, his original partner, being largely confined to books like Teen Titans—all of which helped solidify the idea, despite Robin having been almost omnipresent before that point. However, as the 1990s wore on, Batman's status as a loner saw increasing cracks: first with the introduction of Tim Drake to serve as Robin, then the gradual expansion of the Bat-Family to include figures like Azrael, Huntress, Oracle, and the Cassandra Cain Batgirl, along with Nightwing taking a more active role, and then him becoming an active League member again in JLA (1997). By the 2000s, and when adding in many Wolverine Publicity moments, Batman had seemingly become one of the most sociable and well-connected characters in the DCU—even moreso than he ever was in prior years. Despite this, he's still obligated to be seen as a loner even though it's almost entirely an Informed Attribute at this stage.
The DC ComicsCrisis Crossover event Infinite Crisis has one from a development and story perspective. Originally, of the many characters who died in the event, the biggest name would've been certified A-lister Nightwing. To set up Nightwing's death, the city of Bludhaven that he adopted was destroyed, with the reason being that if they were going to kill Nightwing, they were also going to kill his home. Except, he was beloved to the point that the writers threatened to leave the company if the editors went through with itnote The actual scene where he would have died did survive in the final version, in which he would have been killed by Alexander Luthor Jr., but the outcome was rewritten as a coma. Ultimately they won out, and it was Superboy who died in his place. However, by then it was too late as far as Bludhaven was concerned, and in the actual event it still gets destroyed despite contributing nothing to the story (other than more destruction, of course). In fact, this created problems later on, as it forced the writers to move Nightwing to New York City (which didn't take) and yet they couldn't bring Bludhaven back because they needed Infinite Crisis to have lasting effects. Overall, it's unlikely this would've happened at all had these real life events not transpired.
Shazam!'s archenemy Black Adam inexplicably pointed ears were probably meant to give him a demonic appearance, but then it became silly (and made him look like the Sub-Mariner's long-lost twin). Post-Flashpoint, it's been dropped, and he now has normal human ears.
In-universe, this happened to the Comedian in Watchmen. In his early career, his gimmick was that he was a wisecracking daredevil who wore a canary-yellow clown suit. Some years later, he revamped himself as a Captain Patriotic government agent, and the only remaining vestige of his old costume and theme became a small smiley-face pin in a sea of black leather and body armor. He still calls himself the Comedian, though - according to him, it's because his philosophy changed to be less about telling jokes and more that life is a joke and he's the only one who finds it funny.
