As world champions go, Giardello was kind of ordinary. Joey was competitive in a lively era with a lot of good fighters, but never was head and shoulders above the rest. I'm thinking Hagler would have had a clear win in a good fight. Conn was little more than a middleweight that dominated the lightheavyweight division and was a player in the heavyweight division. He gave Joe Louis, one of the best fighters ever , one of his toughest fights , giving up significant height , weight and reach advantages. Probably Conn would have done to Hagler what he did to Zale, totally outbox and out fight Marvelous al the way.