I would keep the macro story the prequels story told, as I believe that was the one positive. I like Palpatines rise to Emperor, as each movie he gains more and more power through the political process, as it sort of mirrored the rise of Hitler in the 1930's. I know Lucas/Spielberg are big WWII buffs, so I think Lucas took alot of themes of the rise of Dictators during that period.

I always liked the Senate scenes in Episode I, and thought it really gave the OT story a larger scope cause it changed it from this small story about a band of rebels to an epic struggle that trickled down all across the galaxy.