Whilst they did some interesting things with his character at the end of last season, imo he was the least funny of the 6 regulars, so it's not a huge loss.
I'm pretty sure he was happy to leave. They didn't really give him funny lines (then again, they didn't give them to anyone) and then made his character gay in about 10 minutes without anything leading up to it. Unless you count dating Lily and hanging with Whitney and Roxanne a good reason to turn gay. Actually, it kinda is.
Damn it. Now I think Alex and Mark should be super gay, too.
I don't blame him. They changed his character around entirely. He was only with the group becuase he was engaged to Lily, so it makes sense that now he's not with her he wouldn't still be hanging out with all of them.
They tried incorporating a story, but that didn't work either.