I certainly don't think Rick McCallum is making any creative decisions that are getting in Lucas' way, I think the man's only job is to stick around to give Lucas rim jobs at the end of the day, and to tell him how perfect everything he comes up with is. If by crowding his vision you mean stroking his ego and reaffirming Lucas' inflated view of himself and his misconception that he is THE master story teller and can do no wrong, then yeah, McCallum is crowding the hell out of Lucas' vision.

What Lucas' vision needs are a few people to say, "Well George, that sounds interesting, but maybe we should go a different route..." instead we have Lucas shooting down the creative contributions of everyone else and telling them "That sounds good. But not for MY movie." That is why Lucas is failing, because he turns a deaf ear to the advice of others. His near non-existent "creativity" could use some good crowding these days, it is getting pretty thin.