As for CGI giving more flexibility, that can come around and bite ya in the ass. The prequels are the result of having too much freedom to change things.
I agree with an earlier poster.....they shoudl keep it real as much as possible so there is something for the actors to react to. I find that many CGI movies, not just Star Wars, suffer from this same problem.
I think CGI is great for background and space battles and stuff, but not for actor footage. Keep it totally real.