Smulch is a bad tank. There are a lot of things he doesn't really understand (he thinks hp is an unimportant stat for tanks), and there are encounters that he can't wrap his head around to tank them effectively (Huhuran). Plus, he REFUSES to talk on vent, even in cases where it is incredibly useful (Nefarian).
While he did have qualities I appreciated (he was a strong proponent of killing the raid dragons before the GLs grasped that they were necessary for endgame progression), he was for the most part incredibly argumentative, disrespective of other guild members, and more than anyone else I've seen in Warcraft he seemed to gather no enjoyment from playing the game.
Inevitably, his attitude led to him being widely despised within the guild. He eventually decided that he had enough of us, respecced fury, and told people he was quitting in ten days. The GLs decided to kick him after two.