The problem with mages in the 19 bracket is that too many of them want to stack as much fire damage as possible and barrel into a Warsong doing huge crits. The problem with this is that 10-19 WSG is absolutely flooded with rogues and hunters that will tear into a clothie.

That said, mages that stack stamina and spec frost are an amazing asset to any 10 man premade or arena team at 19.