5. Bruce Banner/Hulk – The MCU
Thor is just one of several MCU movie characters that changed drastically: other major heroes did, too. Obviously, we’re not just talking about the recasting of the role, because that sort of change is unfortunate. Though Mark Ruffalo generally makes a far better Banner than Edward Norton, the character’s needless personality shift is impossible to ignore.
In The Incredible Hulk, Banner is a man seeking to control the beast inside of him. By the time he reappears in The Avengers, he’s become withdrawn, anxious, and reluctant to ever lose control. Facelift notwithstanding, he’s like an entirely different man.
What’s more, Banner’s big green alter-ego changes, too. In his early appearances, Hulk and banner are one and the same, but Thor: Ragnarok introduces the idea that Hulk is actually a different personality with his own thoughts and feelings. Then Avengers: Infinity War changed him again, trying to reconcile all the various ideas about Banner and Hulk and only really confusing the issue. In spite of all that, we still love Hulk, so it’s probably fine. Confusing, but fine.