as far as what event brings about this fracture in his personality is anyones guess. I thought that it might be some sorta dominering stance that Palpy had over him. This move would have begun before the events of AOTC. Which is one of the reasons why I didn't like Lucas' choice about the amount of time that passes during the movie. He needed to make a longer movie with a longer period of time passage during the course of the movie. Ditch the clone army story. The idea of a government that doesn't have an army is perpostorous! Even Isreal had an army during the time that they were a theocracy! And ditch the whole jango fett thing. If you want to make him a mercanery for hire out for palpy, padme, or some other senator of importance, than fine. but don't take up too much time on it, he's a third teir character, he doesn't need alot of time on screen. Keep the air of mystery about him and boba fett.

Heck, change all the PT movies, they all lack greatly in the story department. Clones are pretty much a cope out if they just serve a shallow purpose. We need to see the seeds planted in anakin that fracture his personality from Ep. I. Those kinds of things take quite a while to grow and we need to see that in anakin. The story has too many political manuverings in it. We didn't fall in love with the O OT because of the political part of the story, we fell in love with it because of the characters and the dynamic between them. The same needed to be with the Prequels.

Make Obi-wan the good father to anakin. And make Palpy the evil father that twist anakin into believing that Obi-wan is the evil father. Something like that would be far more interesting than what is there now.