I feel like there could be a whole movie on just tying up the loose ends and various inconsistencies he has created. This MAY contain "spoilers", but I fail to see how there can be a spoiler for Ep. III if you've seen TPM and AOTC and the OT. Still....if you're the slightest bit timid, don't read the following..........
1. R2 and 3P0 have to somehow: stop serving Anakin and Padme, become the property of Captain Antilles, and (although I HATE this explanation as being way too simplistic and just an easy error-fixer) have their memories wiped. I almost wish that 3PO hadn't been made by Anakin -- that way he at least wouldn't have to have his "memory wiped", but how else do you explain him not remembering Tatooine and Owen, for starters?
2. Obi-Wan: has to somehow serve Bail Organa in the Clone War. He has to talk with Owen at some point and say "hey, give this lightsabre to little Luke when he's old enough" and be denied.
3. Uncle Owen: according to Obi Wan in ANH, Owen didn't agree with Anakin leaving to fight the wars. OK, well, so far that's a lie because Anakin took off from Tatooine the last time we saw Owen, so unless he goes back and they get in some type of argument, there's another inconsistency.
4. Darth Sidious: this guy has to reveal himself. If GL has pulled a fast one and he's NOT Palpatine (which would be stupid), then we have to find out who he is, and how he becomes unimportant by ANH.
5. Palpatine: we have to see how he goes from Chancellor to Emperor. He is obviously the EMPEROR in the OT, according to Lucas and the AOTC DVD, common sense, etc. But, if he is Sidious as well, then it's even more unnecessarily complicated. Further, since the Emperor in the OT obviously has Jedi powers, albeit dark jedi powers, wouldn't the existing Jedi be like "hey, Palpy, you used to be a sweet jedi like us!" Seems kinda strange......how the heck will Lucas tie this one up?
6. Padme: OK, she has a lot to go through. She has to have kids, have them separated, split to some other planet possibly with Leia, but then Leia has to be adopted by Bail Organa.....hmm....okay, once again, is this unncessarily complicated?
I'm sure there's more, but these are the things on my mind right now. I know we're supposed to have fun with all this stuff -- and I DO -- I just don't want to have none of this explained, or else when we watch ANH, we'd be like.......WAIT A DARN MINUTE, GEORGY!!"
I know lots of you guys think that Gui Gon or Mace will turn out to be bad, or that Dooku will turn out to be Anakin's papa, yada yada yada ..... but that all makes everything even more unnecessarily complicated! There's already too much going on (although, Lucas could theoretically tie up all those "loose ends" that I mentioned in the last 5 minutes, I guess....)