Oh, those might all be good enough reasons that explain why he turned - I don't have a problem with that! We always knew that it was Anakin's emotions and sort of arrogance and ambitiousness that played a role in him joining the dark side. However, I personally just couldn't make the connection between a calm, cold, calculating, composed Darth Vader of the originals and angsty, hot headed, pissy, irrational Anakin of the prequels... That's the part which wasn't believable at all for me, and that's why he doesn't seem a well-rounded character at all. I heard his character is really great in The Clone Wars (animated series) though, so I might just give it a go to redeem him for me.