Who were these top quality fighters he beat before he challenged for the title? Fringe, regional-level contenders like Monroe, Watts and Hart? A proven flop in Seales? Or Mike Colbert, a guy's high ranking was the result of some serious bribing? The only genuine world level contender he fought on the way to title contention was Bennie Briscoe, who was a decrepit old man by that point. Hagler's resume just doesn't stack up to the greatest of middleweights in history. He has longevity and dominance on his side, but the overall quality is lacking. Very, very shallow era of middleweights.
The thing that always impressed me with Hagler is his super accurate punching. He had such a great jab, and would cut fighters up with that punch. He didn't have any one quality that jumped right out at you, but as a package he was excellent. His switch hitting as well...shifting seamlessly from lefty to orthodox and back. Great movement too. Just a solid, solid all-rounder. At his best, he was about as complete a fighter as you'd find. But yeah, He Grant nailed it. This is a super deep division and although I can't see too many fighters beating him outright, I do think there are a fair number that would give him a lot of problems. It doesn't detract one bit from his excellence as a fighter though.