Keeping in mind that the movie was filmed during the writers' strike, which prevented Orci and Kurtzman from doing revisions during filming, this is what I would do to improve the film.
The script was completed and accepted months before the strike - if the producers had felt that plot, structural or any other major changes were desirable they would have completed those in plenty
of time. Those are the very sorts of changes you make every effort to avoid during shooting.
What might have been done and could not be done during shooting because of the strike were minor on-set changes to dialogue - Abrams supposedly thought of "a great line" one day and could not use it. We're not even talking about adding in some kind of expository lumps intended to paper over plot issues, mind you.