xhonzi said:
Other than that, I like your take on the well-intentioned but gullible and weak willed nature of his character.
I have to say, I don't like the gullible or weak willed take on him. Vader was never a character who suggested a lack of intelligence to me, certainly not a lack of will power.
He has intelligence and will power, he just uses them for evil.
The question the prequels need to answer is why a once good man would do this. I may just be repeating myself here, but when you live a state of chaos there is a natural tendency to seek out order - if the chaos is great, you may sometimes even seek out a rigid, confining order - not just outside yourself, but inside yourself also. Just as the outside world of the galaxy would have been wrecked with conflict, so Anakin's inner-world would have been boiling over with fear, anger and desire.
A Jedi's life is all about facing such conflicts, but finding inner-peace through discipline. Facing outer horrors but maintaining inner sanctity. The war Anakin found himself in, however, was too much for him and he sought an easy way out of the suffering, an easy way to silence his troubling emotions. In the pursuit of this, he made himself "more machine than man" and transformed himself into the kind of monster he'd been fighting all along - "Battle not with monsters, lest ye become a monster" and all that.
The disorder of the galaxy caused him pain and he was desperate to be free of it. To this end, he tried to rid himself of that which personally caused him pain - his very humanity - and that which was the origin of the pain to begin with - the disorder of the galaxy.
There's even a hint of this being the case in Return of the Jedi. When Luke asks Vader to come away with him, Vader says that "Obi-Wan once thought as you do". It may be that Obi-Wan had once entreated Anakin, then suffering emotionally, to simply give up on the galaxy - to seek out the life of a hermit so as to maintain spiritual sanctity, even at the expense of participation in the material world. The alternative was, after all, the Dark Side.
I'm rambling now, but this is all stuff that will eventually be included in my alternate prequel outlines which I'm slowly working on in the Script Writing and Re-Writing forum.