JD,
JJ's people arnt yes men and he has a much more massive amount of control than you could phanthom. As prior stated he has fought for core elements such as practical sets, location filming, actual miniatures, as limited as possible usage of CGI, shot on film... No other director would have stepped on on those points and held true. The issue is going to come back to the time frame thats been set by the suits for the films release. I suspect, just as with the original Star Wars, the film wont be completed as visioned upon release and tweaks will be made during or after the initial release. Just a hunch is all. That release date, again as prior mentioned, isnt practical for whats on the table. But that date is set.