Mark Breland, Johnny Bumphus, Naseem Hamed, Brian Viloria, Junior Jones, Greg Page, Riddick Bowe, Tommy Morrison, Gerry Cooney, Andrew Golota, Buster Douglas...

I guess they've crossed past as "prospects", some of them champs briefly, but they still underachieved bigtime, for perception was, they would have conquered. Still a lot more... If given enough time to nudge this brain.