Re: Iron Man 3 - What does it tell us about Phase 2? (Major spoiler warning)
I don't think Avengers 2 outside of more cosmic/time-travel stuff will be any more risky.
If the movie fails to click people could abandon the Marvel cinematic universe altogether.
They need something safe and reliable but just as fun and exciting as the original.
"Don't listen to scientists, academics, fact checkers, journalists, constitutional scholars or intelligence agencies. The truth doesn't matter, only blind obedience" - any authoritarian regime