This little tidbit of information was hidden in yesterdays casting news story by DEADLINE HOLLYWOOD. I can't believe no one bothered to post it.
According to Mike Fleming with DEADLINE HOLLYWOOD, Joe Johnston has already briefly left the Captain America film. This was in response to Marvel informing him that his budget was too high and that he would have to take a cut in pay. Apparently the two sides came to some kind of agreement and he has returned to the film.
I don't know about you but this movie doesn't seem to be coming together with any of the fluidity possesed by the other Marvel movies we have seen. It seems way too early for walk offs to be taking place.