I'm pretty sure that (anyone correct me if I'm wrong) the Sith want revenge for being cast out of the order or something like that. Ever see Star Trek: Insurrection? I always kinda thought of them like the Sona in that film (to some extent anyway). The Sith are also definitely looking for revenge because Darth Maul says it in Episode I, "at last we will reveal ourselves to the Jedi, at last we will have revenge." I feel that it works with Return of the Jedi because a Jedi will not seek revenge, but a Sith sure will. It goes back to when they made the title for Jedi, which I'm sure you know was originally Revenge of the Jedi. The title was changed for the reason that I stated earlier, and because Episode III is about a Sith, it just seems fitting. To me it seems that Anakin hopes to get revenge in some form as well, against the Jedi Order and his master for not trusting him or something. He feels that they are stunting his growth as a Jedi and not taking him seriously, like he said "it's just not fair!" He also thinks they're lying to him, "I know there are things about the force that they're not telling me." So I guess if you are as misguided as Anakin, you might want revenge.
Overall, though, I wasn't really impressed (prepare for blaspemy!) with Williams' work for most of the prequel films
BLASPHEMY! Of course you are entitled to your opinion. But you should really take into account that a fair amount of his work for Episodes I and II was edited and tracked beyond recognition. I hope you don't replace too much. You should listen to the stuff on GoodMusician's complete score that was not used in the film.
Also one last thing about the crawl, I don't like Jedis either, forgot to mention it. Again, other than that, great.