During the Knightfall story arc, Batman was temporarily paralyzed by Bane and gave his cowl to Azrael, who quickly became a Knight Templar after his latent brainwashing was accidentally triggered by Scarecrow's fear gas. This forced Batman to undergo Training from Hell under Lady Shiva to fight AzBats and reclaim his old identity. AzBats turned out to be a deliberate Take That! at the fans who wanted Batman to be closer to The Punisher than, well, Batman. ("You wanted Needlessly Violent Batman? There you go!") Probably the only people that were all that thrilled with the character becoming Batman were the makers and players of Batman Doom, a high-quality Doom mod. However, post-Knightfall the character of Azrael gathered a respectable fanbase in his own right, with a solo series that lasted for 100 issues. The character was revived in 2015 and has regularly appeared in comics ever since.
Cheerful and lovable circus brat Dick Grayson was replaced by cheerful and lovable circus brat Jason Todd in the early 80s. Then, post-Crisis, in a rare case of a character being replaced by an Anti-Hero version of himself, Jason Todd was retcon'd into an eleven-year-old street kid who jacked the wheels off the Batmobile.
Following his death and resurrection, he also spent a bit of time as a psychopathic version of Nightwing. Then, during the Battle for the Cowl event, Jason would also take up the mantle of Batman after his apparent death and became a gun-wielding psychopath. He was played as the villain of the story, however.
During the aforementioned Battle for the Cowl, Two-Face also attempted to become the next Batman and Hush impersonated Bruce Wayne with the help of Magic Plastic Surgery.
During the Batman and Son storyline, fake Batmen began showing up in Gotham City and committing crimes, and Bruce was forced to fight them. The eventual source of these was revealed to be psychological experiments conducted by the Gotham Police Department to create replacement Batmen should anything ever happen to the real one – this didn't turn out so well. One of the replacement Batmen, Michael Lane, went on to become the second Azrael.
Robin Damian Wayne is more of an Anti-Hero than his predecessor, but new Batman Dick Grayson has made it his goal to craft him into a true superhero and not an Anti-Hero.
Cassandra's Batgirl outfit was previously worn by the Huntress during Batman: No Man's Land, who played it straight.
During the Titans Tomorrow arc, a potential future version of Tim Drake becomes a gun-wielding Batman.
Downplayed with Terry McGinnis of Batman Beyond, a hotheaded, sassy juvenile delinquent who originally became Batman by stealing the Batsuit, but he's as heroic as Bruce was, and more approachable than the grouchy loner Bruce. And for the record, his delinquency charge was because he was manipulated by a manipulative friend.
In the "Death of Superman"/"Reign of the Supermen" story arc, Superman was killed and replaced by four guys who were all across the spectrum on this:
Manof Steel was a complete inversion of this; if anything, he was even more heroic than the original. Also, unlike the other three, Steel admitted from the start he wasn't really Superman, but that he was trying to represent the spirit of what Superman stood for. He ended up getting his own comic.
Superboy came out swinging as a cheerfully-amoral Unscrupulous Hero. While he was a legitimate crimefighter, he was fighting because being a superhero got him fame, fortune and hot chicks. He worked for Lex Luthor, and later sold out to crooked talent scout Rex Leech, in both cases because they threw money and pretty girls at him.
Last Sonof Krypton, aka the Eradicator, was the real Anti-Hero Substitute. He was initially a brutal, inhuman vigilante, and it took a talk with Steel for him to mature into a more heroic figure. Even then, he remained ruthlessly logical and had few qualms about killing.
While neither passed themselves off as Superman, both Magog and Proteus tried to usurp his position as the DCU's foremost superhero by being more ruthless, aggressive and proactive. Both were deliberately set up to fail; Magog went too far and Proteus was evil from the start.
Also, in the Justice League mini-arc 'Hereafter', after Superman vanishes from the face of the planet after Toyman manages to pull of a successful attack on him, Lobo, of all people, tries to step in as his replacement.
The original Supergirl -a classic Cape- was killed in the Crisis on Infinite Earths and replaced with Matrix, a shape-shifter mass of protoplasmic matter who took shape of a blond woman wearing a female version of Superman's costume for unexplained reasons. Matrix was unpredictable, prone to sudden outbursts of violence, and wore a Stripperific, spiky version of her costume for a while. To sum up, DC replaced Kara Zor-El◊ with this◊.
Later on, Matrix merged with a troubled human girl named Linda Danvers. Linda◊ was also replaced with Cir-El◊, a black-wearing, angry, angsty edgy teenager with a dark and troubled past. Cir-El was very unpopular, and she was soon replaced with a modern version of Kara Zor-El, who was also initially more abrasive and angsty than her pre-Crisis version - this was unpopular with fans and was eventually retconned as due to chronic Kryptonite poisoning, thus restoring her more idealistic and happy personality and finally inverting the trope.
In Wonder Woman (1987): The ContestWonder Woman was forced to give up her name and costume because her mother had a vision of her death. Her place was taken by Artemis, but in the end it was she who was killed, not Diana. The trope was also deconstructed, as Artemis's arrogant, abrasive and often overly violent conduct in the role undid a lot of Diana's hard work in getting Man's World to accept her and the Amazons and rubbed many of Diana's former allies up the wrong way, thus making things much more difficult for her than they had to be.
This was essentially an update of an older story from the 70's, wherein Diana was briefly replaced as Wonder Woman by an abrasive redheaded Amazon named Orana. Orana was Killed Off for Real the very next issue, allowing Diana to reclaim her costume and identity.
In an inverse of this trope, Green Lantern Hal Jordan inexplicably turned evil during the Emerald Twilight arc and the role of "original hero" as described by the intro was played by his replacement Kyle Rayner.
Played straight, however, was Guy Gardner replacing Hal Jordan in 1985. To clarify: Guy Gardner is not some crazy killing machine or anything (unless you count the Warrior storylines where he's a living weapon); he just has more of a fly-off-half-cocked, kick-butt-take-names, punch-first-ask-questions-later personality than Hal.) He's the gym teacher everyone despised in high school.
While Guy fits, he technically didn't replace Hal. Hal resigned to spend more time with his girlfriend (who subsequently became a more psychotic version of Star Sapphire) and was replaced by John Stewart as Earth's GL. Later, during Crisis on Infinite Earths, a faction of the Guardians healed Guy from a coma and gave him a ring and mission. By the end of that mission, Hal was a Green Lantern again.
Happened, of all people, to The Authority once, when they were defeated by G8's agent and replaced with bunch of Nineties Anti Heroes. For many people Authority are a bunch of Jerkassses at best and Villain Protagonists at worst, but comparing to replacements they look like fricking saints.
Of course, the second the real Authority comes back, they start their revenge by killing in cold blood the only redeemable character among the new team: Rush, the Canadian replacement for Swift, who didn't kill anybody they wouldn't have and hated all her teammates. They catch hell for this later.
Wally West subverts this, thanks in large part to his Character Development. When he took over the mantle of the Flash in The Flash (1987), Wally was initially quite a selfish Jerk with a Heart of GoldDeadpan Snarker looking to find a way to make a living off of heroics, but he also suffered from terrible depression and low self worth after Barry's death. However, several events (such as befriending the retired former villains The Rogues, especially the Pied Piper, and Chunk, a metahuman who accidentally caused massive property damage) showed Wally had a completely different view of supervillains, treating them with an open mind and acting more like a social worker, compared to Barry Allen who, as a police scientist, treated his heroics like cop work. Wally's subsequent Character Development had him grow out of his jaded selfishness and he became probably the most compassionate of the Flash franchise, and even more of The Cape than Barry.
Happened to Wally West with Dark Flash, a mysterious character that turned out to be an alternate universe version of Wally who went by Walter. Unlike Walter, Wally wasn't able to save Linda Park in his equivalent of the Terminal Velocity story, and received some training under his universe's Savitar (a villain Wally defeated) before killing him. After Wally and Linda end up in his world, both were seemingly killed by Abra Kadabra, and Walter swore to avenge them. He started wearing a darker outfit and traveled to the main DC Universe. He was distrusting of other heroes and didn't reveal his identity to all but a select few, and was a bit more brutal in his methods. When Wally and Linda return, Walter is forced to leave, as he and Wally couldn't occupy the same universe for too long.
In The Flash (2011), Future Flash was a Barry Allen from a future timeline. He wore a blue outfit and killed his villains, because his failure to save the new Wally West resulted in him snapping and travelling back through time. Notably, he killed his villains on his way back, even though his plan would mean their actions wouldn't happen anyway. He fought the main Barry, who eventually got stuck in the Speed Force, and Future Flash took his place for a while. He eventually died.
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