This bit comes from
AICN:
"And I’m going to get a little more involved now with what goes on with the other movies. I’m very excited about Kenneth Branagh, I can’t wait to see his take on THOR and we’re really looking at the Cap stuff, very closely.
For one because we put the shield in there and Tony’s legacy… Howard Stark’s legacy somehow is related to… there’s some relationship between Tony’s father and what was going on in World War II, in the Marvel Universe, and Shield, so we’re trying to lay some pipe here so that when it all happens it feels somewhat inevitable.
But there are a lot of tonal challenges that are going to take place, more so in the other films I think. THOR has a tremendously… that’s going to be the most difficult one to integrate into this reality. And if it can be properly done then you get a great version of AVENGERS. If not, AVENGERS is going to seem like ROGER RABBIT with different cartoon characters from different worlds, you have Betty Boop next to Daffy Duck next to Donald Duck you know. (laughs)
And I don’t know that’s the experience it should feel like, it should feel like a unified Marvel Universe. And I know that the Marvel guys are very, very vigilant about that.
You can get the entirety of this awesome interview
HERE.