It has, but he did a filtering process to disregard names and reapply names back into the script just to see what works/sounds better. Luke use to be "Justin Valor" and Obi-Wan Kenobi use to be someone else, and the emperor use to be called "Cosdashit" (kid you not). Imagine if Lucas had gone with that instead of "Palpatine." How stupid would that be? Well, it is because we get a ridiculous name like "Dooku." It seems like Lucas didn't go through the same process he did for the OT. He didn't switch it around to see if it fit. Instead, he seems to go with the first thing he puts down. Not a very good writer approach.