I love Episode III. It is a galactic Greek/Shakespearean uber-tragedy. I love seeing the good die, and those good that succeed them become evil. The sequence of Anikin turning into Vader is just plain goddamn awesome. "I hate you!" he says he says to Obi-Wan. The dialogue may not be great in that sequence. Palpatine says, "It seems that you killed Padme," with a weirdly happy musicality. But the words can only be forgotten after one sees the brand-new shine of Vader's helmet.
I think that Vader is a hero in the same way that Satan is the hero of Paradise Lost. I consider it heroic to rage against the way things are, and to maximize personal control, to attempt to change reality by the exertion of one's personal will. The problem with "The Greatest Story Ever Told," the story of Jesus Christ, is that J.C. always knew that he was going to die for everyone's sins. Vader does everything that he can to save what he is attached to, and these actions not only ensure his own destruction, but the destruction of the entire Republic. That is excellent tragedy, in the Oedipus Rex line. Power can be both a force for good and for one's demise.
So yes, I want to see III again, because I love to see how tragedy offers us access into understanding the turn to evil, which is a possibility within our human natures, and not something external which we can push away, curse, and refuse to think about with easy catchphrases including the words "Hitler" and "Nazi."