1000 Misspent Hours argued that Jigsaw's motive (targeting healthy people who are wasting their lives, which enrages him because of his terminal illness) is the smartest idea the movie has, but the movie wastes that potential by focusing too much on the one victim who doesn't fit the pattern.
1000 Misspent Hours praised the first three films' storyline of Jigsaw training Amanda as his successor, only to learn that her madness is antithetical to his, but considered that it's undermined by the series' typical approach of holding back a lot of information to use for twist endings instead. Later in their review for Saw V, they stated that it was further undermined by the following films giving Jigsaw another apprentice who does share his ideology, making the outcome of Amanda's test meaningless.
Saw V sets up an interesting, potential arching rivalry between Strahm and Hoffman as the former begins to unthread the latter's involvement in past crime scenes of Jigsaw murders, which could have fit well as a final main Story Arc spanning over the following films. The moment Strahm gets his first direct confrontation with Hoffman, however, he's quickly killed off in a way that didn't have much impact story-wise. It gets easily infuriating because Strahm was the most competent protagonist by then and could have easily served as an antithesis and major opponent to Hoffman. Judging by the announcements given for Saw VI's greenlight, it appears that the production staff were meant to follow on a "Strahm vs. Hoffman" plotline, including the confirmation of a potential ending where Strahm killed Hoffman, but for some reason they didn't go with it.note Patrick Melton was the only person who spoke about this so far, claiming that it turned out to be too complex to put in motion.
Unlike previous and future protagonists in trials, William seems to have made a genuine Heel–Face Turn by the time he enters his final test. In an opportunity to give a fresh resolution where a Jigsaw game actually succeeded in its goal to rehabilitate the subject for once, William instead gets brutally killed just because his survival wasn't up to him to begin with.
Some fans felt it would have been a far better ending if Jill had actually succeeded in killing Hoffman, then decided to take over the Villainous Legacy of her late husband once and for all and emerged as the final Big Bad of the entire series. Instead, Hoffman escapes the Reverse Bear Trap 2.0, which admittedly serves as an awesome moment for him, but results in the next film being a far more standard-issue entry with Hoffman as the villain yet again, and Jill just playing the part of a Damsel in Distress until Hoffman eventually catches up to and kills her.
The film's director's cut includes, to date, the series' only post-credits scene. It concerns a guilt-ridden Amanda going to Corbett's cell and warning her through the keyhole not to trust the man who will rescue her. The scene loses much of its impact with its placement at the very end of Saw VI, when it's already been established beforehand that the FBI (and eventually the local police in 3D) no longer trust Hoffman. It would have had much more dramatic effect if it had occurred at the end of Saw V, as that whole movie had been establishing that A) Hoffman was seen as a hero by law enforcement for "surviving" the onslaught at the Gideon Meatpacking Plant and saving Corbett; and B) by V the FBI was buying into the notion of Strahm being the new killer much more so than they did Hoffman, and thus would have a little thread for them to pull at and foreshadow Hoffman's eventual unmasking in VI (and explaining why Perez taunts Hoffman that "everyone" knows about him in her last words); and c) it would have been one hell of a vindication for Strahm's unfortunate fate given Hoffman is a downright Karma Houdini (and quite literally so, managing to "magician" his way out of the crushing trap) at the end of the movie. Granted, it may have been a scheduling issue if they couldn't have secured Shawnee Smith to film the scene in 2008, but regardless. Hooray for fan edits!
The movie introduced two interesting plot points: what made Lawrence join Jigsaw and the Jigsaw Survivor Group. Both of them were ignored in favor of Bobby's storyline (as well as the plots of the following installments); the Jigsaw Survivor Group only serves as a mere Continuity Cavalcade, and Lawrence's role amounts to little more than a cameo, without telling anything that fans hadn't already guessed years ago (especially considering that it was the canonization of a popular fan idea at the time). Lawrence's plot was going to be continued in a planned follow-up, but most concepts regarding it were scrapped as a consequence of Saw 3D being the result of Executive Meddling cramming the original Saw VII and Saw VIII into one movie.note Depending on your view, the way the Jigsaw Survivor Group was left out could also be granted, considering that it was originally planned for most of its members to be revealed to be Jigsaw accomplices alongside Lawrence, which could have arguably rendered the whole point just as (if not more) undermined.
The movie also begins with a new concept: a trap appearing in public, where three victims are sealed behind bulletproof glass in front of a busy street. This could have been a very intriguing subplot (how does the crowd react, the societal impact, the added difficulty of setting these traps up without being discovered, etc.). Sadly, it's never followed up on besides Word of God confirming that the two pig-masked men who helped Lawrence kidnap Hoffman were Brad and Ryan, the survivors of the trap.
The film's posters and viral marketing campaign would have you believe it deals with the lingering influence the Jigsaw games have had on society, with the antagonists being a cult-like group who are carrying on their "savior's" work. Instead, this is only mentioned once as a fansite on the dark web, and the ending is basically a repeat of previous entries, with the reveal of yet another apprentice, who somehow used to work with John before any of his other disciples on top of that. The twist that the main game is a Stealth Prequel to the entire franchise also renders the whole thing inconsequential, and can make you wonder if this is really a story that needed to be told.
argued that Jigsaw's motive (targeting healthy people who are wasting their lives, which enrages him because of his terminal illness) is the smartest idea the movie has, but the movie wastes that potential by focusing too much on the one victim who doesn't fit the pattern.