I couldn't stand him in the first couple of seasons, but the character matured by the time the third year kicked off. It's a shame that they wrote him out when they did, the character was working pretty well at that point.
I blame fan hate mail for that.
It's one of the shames of being a Trek fan IMO. Many times fans take stuff to personally, too the point where they even sent the actor himself threatening hate mail. He was just a kid, how bad does it look on us knowing that adult fans sent a child actor hate mail just because of the character he plays?
Many believe that Trek fans are intelligent and are of a better class of people, that just proves that we clearly aren't and we should be ashamed of what we put that young man thru.