Originally Posted by Spider-Fan
Dude, Cap 3's BO would go down TREMENDOUSLY if you killed off Steve Rogers and made Bucky Cap. Interest in the character is immediately lost, and the film will suffer. Thor could make sense given Hela's involvement and such, but that still involved Hemms and he isn't actually dead (he would be "technically" dead). But, I think a Thor film based on Ragnarok would be a better Thor 3 than escape from Niffleheim. (most probably would agree). You can't permanently kill Thor or Cap, and then expect the BO to increase. It will only lose money and there is little logic in doing it financially.
It depends on how Bucky is received in TWS and Avengers 2. "Captain America: Fallen Son" about Bucky trying to live up to Cap could pique interest if done right. New protagonists have been done well, with Bourne Legacy, GI Joe: Retaliation, and a whole host of video game franchises. The idea that killing off or replacing the main character removes all the appeal of the franchise is false. After all, if people feel like A) the same story is being continued and B) They like the new guy as much or more, why wouldn't they show up?
I do agree they would want to bring Steve back though... how and when is anyone's guess, I think. I also like the idea of Thor. I say kill 'em both!