Wolf is my alt (Toon Link is my main). Even so, he *****. Seriously. I can sand bag with him, and three stock pretty decent players (IRL of course) without breaking a sweat. There are characters that are harder to beat than others, but nothing I would consider a counter. I have yet to play a rival of mine (who has a sick Dedede). However, I have seen him have trouble against another Wolf player. Though the other Wolf player wasn't as good as me, he still gave that Dedede a very rough time.
Wolf's secret to his dominance, is that he controls the center of the stage. His range is long as hell and his attacks come our REALLY quick and pack quite a punch (and have a significant priority too). He is heavy too, so its hard to get him out of the center and off the stage. His weakness is his crappy recovery, of course. If one could only get Wolf off and below the stage, its pretty much garunteed that he won't be able to get back on.
I am SO glad he is my alternate. He is fun to play as, but I would not want to main him. I feel kind of cheap when I use him, especially since I never have to try hard with him. Plus, his recovery is awful. Toon Link is much more technical and requires more thinking, timing, spacing, ect. When I play as Toon Link, and win, I feel that I actually EARNED the victory. With Wolf, its too easy.