9. The Hulk
How Would It Change The Franchise?Mark Ruffalo's Bruce Banner was the breakout star of The Avengers. Everyone who saw the movie came out loving his character. Not bad for a guy whose casting was questioned as not being up to the standards of previous Banner, Edward Norton. The Hulk is one of the most powerful members of the Avengers, and how better for Ultron to demonstrate his super-villain bonafides than by killing off one of their powerhouses? The ways in which this could impact the franchise are varied. For one, it could be a fake-out, and maybe Banner would simply lose his powers, and that could open the door for other iterations of the Hulk. Or maybe his death leads to the introduction of his cousin, She-Hulk. Or, since the Age of Ultron comic book story dealt with time travel, maybe the Hulk gets shunted off into time, paving the way for a Hulk: Future Imperfect movie.
Will It Happen?I could see it going both ways. On the one hand, Ruffalo does have a contract with Marvel, so it's not likely they'd kill him off. But on the other, there isn't a Hulk movie in development and the Hulk TV show seems to be dead in the water.