1. Spider-Man 3
A film so disappointing to the extent where it stopped a perfectly good series dead in its swing, forcing Sony to go for a sequel obsessed reboot, Spider-Man 3 is the point where studio involvement overpowered Sam Raimis sensibilities. The most maligned scene of the film is when Peter Parker embraces his emo side and goes for a little dance, much to the dismay of everyone in the cinema. But as terrible as that scene may be, theres a much deeper underlying problem with Spider-Man 3. Personifying a third entry just retreading whats already been done; we get Peter becoming disenfranchised with his alter ego, a villain turning good at the end and Mary Jane gets kidnapped in an evil master plan. Even the non-super side of the plot is just a time developed version of the previous two films, having Peter failing at life, only a little more privileged this time. The more showy elements are what people remember, but those are also the more daring and different elements in this exercise of repetition. Rami originally didn't want Venom as part of his film, instead wanting the focus to remain on Peters existing relationships with Harry and Ben (his killer at least) and its in these moments where the film does something markedly progressive. Clearly studio involvement (that depressing word again) once more got in the way.
Any more threequels you felt were just copies of the previous entries? Or are there any you expected to be remakes and actually did something new (Dark Knight Rises anyone)?