Watched Star Wars Episode III: Revenge of the Sith with my son today. He loved Episode I (he's 6), and kind of liked Ep. II, so I figured we'd finish with the CG Clone Wars movie and Ep. III.
He became very bored during the movie, and played with other toys, unless there was a fight scene. I tried to explain why Palpatine was a bad guy, but playing a good guy, and that Anakin is a good guy, who actually becomes a really, really bad guy. It all takes place too quickly and with no explanation which makes sense anyway. In the end, my son summed it up pretty well: "Now I don't really want to play that character in Lego Star Wars anymore."
And there's the rub, there's the central problem with all of the "prequels": We all know that the sunny-dispositioned kid, the one who becomes a bad-ass general in the Jedi order, is going to grow up to be the guy who blows up entire planets, or enslaves entire populations. We all know that the neat-o keen Commander Cody of the Clone Troopers is going to be a backstabbing bitch who kills the Jedi, the ones who have saved their asses repeatedly if the Clone Wars TV show is any indicator, kills them from behind, without hesitation.
There are no heroes in the prequel movies. There's no one to root for. And rather than try and find a reasonable explanation (or hire someone to write a reasonable explanation for him), Lucas tries to cram it all into the last hour of a three film epic. WTF.
At least in the Japanese dubbed version, at the very end, Vader only screams an anguished cry, rather than "Nooooooooooooo!"