>>9 Was it really the reason? I don't remember reading that anywhere, but it would be a reasonable conclusion.
>>6 I don't see what that has to do with fitting in with the group. It's not like there's an age requirement, the point is he's a superhero, so he must have his own uses. And the fact that his abilities offer similar things that others would doesn't rule out the idea that he could fit in with the group. You could argue that Thor's strength fits the same niche as the Hulk, and his flight fits the same niche as Iron Man - the point is it doesn't hurt to have more, similarly capable people on the team, unless it's actually the number of members that is a problem.