The real answer to your question in the body of your post is "Haters gonna hate". Wesley only saved the ship..1 1/2? 2 1/2 times? I forget.
In the subject line, what is wrong with him? Everything. His clothes, his boring personality, his lack of chemistry with Bev. No that all this is the writers fault and not Wheaton's. Poor guy. Between the fans and Berman ****ing him over he must have needed years of therapy.