Bernard Duune-chin Ricky Hatton-defense and being able to keep control of his weight Miguel Cotto-no more weird elbows out thing he does
Norris despite his chin was an elite ATG at 154 though, but yes I get your point that he could have been even better if blessed with a good chin.
id give khan a chin. definitely a chin. ali and rjj, the knowledge of when to retire. prince naz, more desire for the sport.