Chad Dawson had the potential to be a HOF'er. Every single trainer he had said he was nearly physically perfect but had no focus whatsoever. He horribly underachieved because his mind was a haze of confusion.
Joan Guzman ruined his career by failing to make the weight in some big fights so stupid, i still think style wise at his best he would've been a very tough match up for Manny Pacquiao. As for the thread.... Juan Manuel Lopez Yuriokis Gamboa
Every single boxer could have done something better in their career even if they "overachieved" but generally boxing is the cruellest sport. The have a "successful career" and make it out the other end alive and healthy is a good a win as possible. George Foreman for example.