Definitely deserves a mention for having a punch so good in comparison to the rest of his overall game. Of course his career wasn't just the left hook, you're leaving out his heart and balls.
Do you notice that there is two kind of great left hooks(head shot/excl RJJ and Wlad) Like with Frazier/tito/morrison. They had the same high from the shoulder left hook. SRR/ODH and everybody else kind of threw it effortlessly from a lower guard.
Ali's hook was underrated. It was a wide, sweeping thing he throw, often as a sorta hook/uppercut against short opponents like Frazier or taller guys when they tried to duck low. Not a lot of power in it but he could dribble it off the guy's noggin' like a basketball, with cumulative effect.
Smoking Joe. To win the heavyweight title and be the first man to beat Ali should give testimony to his left. It was the only thing he really threw effectively.