But, CO is right--the rest of the film does not follow the logic laid out in the "doing it for padme" arc. Lucas was so close to creating a great character film. What happened? Well, the film was not written--or even shot--with the whole Padme arc in mind. It was all added in post-production--even the dream sequences; initially it was just a single nightmare, and not even the primary reason for his turn. But it fell flat. It didn't work because AOTC was a debacle, so he had to re-shift the entire film to a spontaneous, emotional act--saving Palpatine in order to save Padme. This was a stroke of brilliance in my opinion--finally we are dealing with character motivation and emotion here. But Lucas ultimately botched it. Why? Because he didn't rebalance the rest of the film. It was just too late--the film was already shot and in the can, and in order to re-balance it the film would essentially have to be re-shot and re-filmed from the ground up. The problem was that after Anakin turns the film links back up to the initial version where Anakin is "twisted by the darkside". When he accepted Palpatine's offer in Palpatine's original "reveal" scene he genuinely believed that the Jedi were plotting against him and was slowly feeling the darkside and being corrupted by it; in fact, in the original version when he kills Mace Windu he doesn't say "what have i done"--he says "i cant believe the jedi were really taking over." Thus, his decision to go to the temple and kill these traitors was justified, and this links up with what he says at the end--"I should have known the Jedi were plotting to take over...from my point of view the Jedi are evil." But instead Lucas re-filmed the entire arc of his transformation. He re-filmed the reveal scene to make about keeping Padme alive. He added more vision scenes and more scenes about anakin become obsessed about saving padme. He added a scene where Anakin tells Mace about Palpatine's identity. He added the brilliant rumination scene. And he added the great scene were Anakin is absent for the Mace-Palpatine fight, comes in halfway and is goaded by both of them to choose a side--and then choses Palpatine, saying "what have i done...just help me save padme." But now after this section is finished, it returns to the original version--why the hell is Anakin suddenly killing his children, when he was just loyal to Mace windu a few minutes earlier when he told him the truth about Palpatine?? His acceptance of the Sith was a spontaneous emotional response related to Padme, not any sort of personality flaw or corruption/betrayal issue.
Lucas got the first 50% of it right, but then didn't have time--or didn't realise--that the all-important final 50% was not re-aligned in sync with the new story arc. I would rather have the version that exist now and is inconsistent rather than the absolutely flat and totally unconvincing original version. ROTS was imperfect but i thought it was pretty good in spite of these inconsistencies because i felt some emotional attachment to the story and characters for once--Lucas set it up great, and although the ending didn't follow through he at least had me by that point and the terrific action scenes and drool-inducing finale partially made up for the few flaws that remained. If you thought ROTS sucked you can at least be thankful it wasn't as bad as it was originally shot.