About Anakin's turn: I've also been thinking that Anakin's turn should happen in the Council chamber, with the aid of echo-y voiceovers to let us know what he's thinking about (heavy on the Palpatine dialog). Using some better "disturbed" music is a great idea too. Although Anakin's turn has been gradual, I think we still need a moment when it actually happens, DELIBERATELY. The music should really let the viewer know that, when he walks out of the room, he's made up his mind. Are there any long shots of Anakin in the chamber where we can add some Trooperman voice work, like "I can't let this happen"?
I know this is a little weak for the turn, but I don't see that we have much else.
(As an aside, we should play up Anakin's jealousy of Obi Wan and suspicion that he and Padme have a thing going on. The birth of the rebellion deleted scene where they meet with Palpatine is good for this).
OK. So when Anakin walks in on the Palpatine fight, he's already made up his mind about what he has to do. I'll use the "Jedi Confront Palpatine" clip (which I discovered was made by OT.com member Darkhelmet) as the basis of this:
Anakin walks in - long shot.
Mace: (to Palpatine) You have lost.
Anakin steps close.
Mace: I am going to end this once and for all.
Mace rears saber back.
Palpatine (voiceover): Anakin!
Anakin says "NO" and cuts off Mace's arm.
Palpatine fries Mace (and himself) and throws mace out the window.
After this, Anakin does not express any remorse or question himself.
(BTW, the whole Palpatine transformation thing is a mess. I think Darkhelmet handles it pretty well. It's not perfect, but it sorta works.)
Some more thoughts on the lava scene: After watching Marvolo and C3PX's clips, I thought they were both pretty good. However, something about the fades in C3PX's version felt a little weird. (Do we have any other fades in Star Wars?) In C3PX's clip, I did like the idea that we don't see the Emperor come and get Anakin. That always felt a little too mundane. Maybe after the shot of the hand grabbing the ground, we can see the shadow of the shuttle passing over.
I was struck by the lack of the Vader reconstruction. I think this is a very powerful moment that needs to stay in some form. (And let's keep the awesome "Lord Vader, RISE" from the trailer.)
I had another small edit idea for the lava scene. Obi Wan should stay "closer" the whole time he is talking and watching Anakin "die". Only after he thinks Anakin is dead (whether he is or not) does he starts walking up, PICKS UP THE SABER, and pauses at a higher level to look for a moment. A rotoscoped shot of a stationary "dead" Anakin can go here as Obi Wan looks on, and then he walks off as we get the wide shot that pulls away (obviously mute the Anakin wails).
Thoughts on Grievous/Maul: I think this is a good idea, IF it can be pulled off. If nothing else, it helps to give Episode I a little more meaning, and it reinforces Palpatine's obsession with keeping his apprentices alive in a mehcanical suit. The trick is to come up with some kind of scene in Episode II where Palpatine talks about or shows this. Maybe at the end on Coruscant when Palpatine is talking to Dooku and they are walking off, we can just cobble together some lines where Palpatine says something like "I have promising news of Darth Grievous. The Dark Side of the Force has restored him". Trooperman?
If we do this, should we have Dooku remain "Count Dooku" and not be Darth Tyranus? Sort of like he's working for Sidious, but not an "official" apprentice.
OK. That's enough for now.