Josh Koscheck
Josh Koscheck has been an excellent fighter over the course of his UFC career. However, he proved in his recent title shot against Georges St-Pierre that his most valuable weapon may be his mouth.
Koscheck will go down as one of the better welterweights in recent MMA history, but he won't capture a title as long as St-Pierre is competing in the same division, and up-and-comers like Rick Story are already beginning to surpass Koscheck as well.