I don't think Marvel would have Captain America, Thor, and Ironman in an Avengers movie that either came out before or at the same time as thier original movies. Because than they would have to worry about how the character is portrayed between movies and they would also have to keep the same actor. I think Avengers should start out as a nobody team first and once the first big named characters come out with thier movies then have them join the Avengers in the sequels.