Bingowings said:

I'd also downplay saving Padme as motivation for turning against the Jedi.

It would make more sense to have him genuinely believe by the time he sees Mace with his saber at the Chancellor's throat that the secret guilt he feels for killing Dooku and the sandpeople is pointless as Master Windu is about to do the same without guilt or shame.

If the Jedi are no better than Sith he might as well be a respected Sith Lord than a disrespected Jedi.

It should be the moment he stops being the boy Anakin and becomes the decisive man/machine of action Vader.

By the time he comes to believe Padme has betrayed him he no longer cares for her either, his lust for power and revenge has eclipsed his love for her.

Very much agree, and was thinking about this yesterday. Anakin tells Mace not to kill him though he did the same thing to Dooku earlier in the film. If you could pull this emotion off, I think that would be perfect. How too fill in the gaps between these scenes though...