Just the fact that he can grab any projectile and throw it back looks really easy to abuse, especially since we haven't seen any repercussions of doing so. (Like taking damage each time you do it, or for as long as you're holding onto the object, ect. ect.)
As another of my (relatively) Smash-savvy friends told me, he looks like a setup character. If allowed to live long enough, and played by someone with skill, he can kill people pretty easily. The thing we both noticed though, was that most of his shown attacks seem to have considerable start-up times.