He was awful to observe during the early game, but I was able to identify with the reasons he "revealed" to the unconscious Rinoa later, that it can be easier to let people believe you're a cold-hearted a.hole than to face your emotions and your reliance on others. It's hard to really explain unless you were once in that sort of mindset yourself.

I'm in two minds about how quickly he changed. It was a bit sudden, but sometimes these things are. I seem to recall he's talking to some jerk in Horizon and thinks to himself "hey he sounds a bit like me.... what a jerk" and when you observe him from then on he stops being one. In other words, he got to look in the mirror, saw what he was, and adjusted accordingly. Quite admirable.
The other big turnaround being when Rinoa is put into a coma. Then he goes a bit far the other way and is all NOTHING WILL STAND BETWEEN ME AND MY LOVE GET OUT OF MY WAY
I'd say he's never quite uh, perfect. But what human is? He's realistic. All in all I like him yeah.