-The droid stuff at the beginning with R2 could be changed (at least the voices)
-Get rid of the damn explaining everything. (an example is Anakin telling us about the spherical droids on Obi-Wan's fighter) We don't need any more Ric Ollies.
-Obviously find away to modify Grievous, even if it means deleting most of his scenes.
-get rid of midichlorians. So what if we don't know where Anakin comes from? The alternative isn't any better.
Then there's things I would do:
Make Anakin's character less confused. I know that Anakin was supposed to be skating the fence on who to trust, but it was somewhat poorly done. I think there is enough material to make him more one-sided (both before and after he learns Palp's true colors) by deleting certain stuff. At least make it 75/25 instead of 50/50. To me, it never seemed that Anakin fully turned to the darkside, there were certain scenes that were contradictory and/or ambiguous. One example is his regret of helping to take out Mace. Cut this. Basically just streamline the Palpatine manipulation machine on Anakin and focus primarily on the promise of saving Padme, and less on politics. That way there's more of an impact of him turning to the darkside
-Cut some of the fast-cuts during the battle scenes. The were overdone. Slow things down a little.
-Delete the "she's physically fine, she just lost the will to live" line
I would even go as far as to severly trim down the Yoda v. Palps scene (while also putting it before the Anakin v. Obi-Wan duel). At least make Yoda seem like he is winning. I say this because I don't understand why Palps sees the need for Vader after the end of the movie, if there's no threat (virtually no Jedi and no rebellion yet). If he sees Yoda as more powerful, perhaps he knows he needs Vader's help.
Again, these might not be possible, but it just seems with some selective cuts things could be more concise.