I don't fault Lucas on the story of the PT, I actually like it, and though the turn is pretty bad, and Padme losing the will to live is contrived, that is all stuff that I would be able to live with had I some attachment to the characters. For instance in ROTJ, I never like that Luke/Leia are siblings, but at that point I was not going to nitpick, and just accepted it and from then on never had a problem. The bottom line is Lucas had me by ROTJ, and he could have done anything without it being too ridiculous.
Anakin had a chance of being the dominant character of the saga in terms of depth compared to the OT characters. Lucas actually got Anakin right with TPM, he is a good kid, or the golden boy as I call him. But for some reason Lucas made Anakin very unlikable in AOTC, and goes against everything he did in TPM.
Anakin should not have been unlikable until he turned, and that would be the whole tragedy, you have this character you love for 2 1/2 movies does something stupid, and you shake your head on why he does it. But now you have this character who I just didn't like in AOTC & ROTS do something stupid, and now my reaction, "Good, he deserved everything he got on Mustafar."
That isn't a tragedy, that isn't an anti-hero, an anti-hero is Dirty Harry played by Clint Eastwood, not Luke Skywalker. An anti-hero is a guy who is beloved by the audience, but you do question the things he does cause he may be arrogant, he may take some liberties with the law, and he may be just as evil as the bad guys in some ways, buy in the end he is doing it for the good guys, so you may not agree with his methods, but you sure as hell understand.
If Dirty Harry is unlikable in that movie, then the movie fails miserably. The whole time you think of Eastwood as this rogue cop, but there is just something you love about his pozazz and charisma that gives him leeway to take matters in his own hands. For Anakin, he just never grabbed me in AOTC/ROTS, and I just couldn't root for him, and that is where Lucas really dropped the ball.