Originally Posted by Spideristic
There needs to be some time passage between two actors taking on the same role. Many will continue to criticize the decision but most will eventually grow to embrace it. Most recent example being for Bruce Banner. I am already on board with Andrew Garfield playing Spider-Man, as he appears to be bringing more of the light heartiness of Spidey back with his portrayal and his genius side will be explored more this time.
After Iron Man 3 and Avengers 2 wraps up if RDJ isn't up for it, they can go with another actor. Sure the new actor may never match to Downey's stellar performance, doesn't mean others shouldn't try.
Comic fans are so used to their favourite superhero comic characters being drawn and written by different people, movie roles for those characters can be adapted in a similar way.
I'm a big fan of Andrew Garfield. Great actor, and very likeable. Definitely helps the transition.
A little bummed that Norton was replaced as Banner but it's not deterring me from watching Avengers at all. Same goes for RDJ; can't think of any other actor playing Stark right now cause he's that good. But if he were to decide that he didn't want to play Iron Man anymore and be replaced, I'd still watch the movie.