I thought that he was moreso the CAUSE of her death than her actual killer. Remember, the med droid said that she LOST HER WILL TO LIVE. Her husband has turned into an evil, murdering scumbag. I think it was just her overwhelming grief that made her not want to live anymore--which is certainly just as tragic.
The whole problem with the Leia-mother thing... I'd believe that she could have special "force memories," I suppose. But then why wouldn't Luke? And her adoptive mother would have to die REALLY soon so she wouldn't be able to remember her and tell the difference. It's just not going to work completely right. I had been expecting Padme to live for just two or three years as a horribly sad woman until her broken heart finally killed her.
Stupid George Lucas ruining my storyline.
All in all, I really enjoyed the film. I saw it a second time today and enjoyed it even more! The destruction of the Jedi was truly very powerful--thanks in great part to John Williams.
I think one of the strengths of the movie that could override the poor dialogue and direction that was still present, if reduced, was the power of the actual story. The other two prequels didn't have an independent story in each strong enough to really engage me. Oh, Jedis crash on Tatooine and have to get this kid to win a pod race! I can barely even REMEMBER AOTC, although I haven't seen it since the midnight showing when it first came out. But the real power and darkness of the story allowed the film to stand on its own and made me overlook other weaknesses easier.
Christopher Lee (who is sadly not in the movie long enough, because he's always awesome) said in an interview that he played Dooku to really be believing that his actions are helping the Senate. His point was that it made Palpatine's betrayal (telling Anakin to kill him) even worse, as Dooku thought they were a real pair that was going to save the Republic. However, I found it most interesting to see two of the Sith having fallen to the Dark Side for reasons of good. Dooku and Anakin both believe in peace and the Republic. And Anakin wants to save his wife. It makes it all the more painful and poignant.
It'd be nice to know what caused Palpatine's fall, but I'm pretty convinced he just wanted the power the Dark Side offered.