Anybody who thinks either of these guys gets "blown out" simply DKSAB, period. If these two faced each other it would very likely be a tactical fight fought from behind the jab. Hagler liked to use his technical superiority to deal with hard hitting brawlers ... and surprise, surprise, Golovkin does the exact same thing.
We're talking prime years. GGG has too many unanswered questions. We know how great Hagler was in his best years.
When Golovkin was prime other fighters were hiding behind the furniture when he walked into a room. It was like magic. Eubank lost his pens, Ward was "busy", Sturm had a new belt created for him so that he didn't have to face him, Cotto paid him off so as not to face him and Canelo flat out vacated the WBC belt rather than defend against GGG. Even when he got older, Golovkin had to pay guys like Jacobs extra so that they would take their mandatory shot. Any questions should be directed at the group of boxers hiding behind the old dumpster.
Canelo would beat hagler by robbery in a very close fight. Ggg would imo beat hagler also in a close fight. Only thing sure it would have been a great war. People underestimate ggg and canelo, both are once in 30 years talents with crazy work dedication exactly like hagler. Ggg in his prime had incredible stamina, faster feet than now and every skill in the book. No one is beating him clearly in the whole history of boxing.
Hagler wins a decision in a competitive fight. I don’t really see it being a war, unless it’s the later versions of themselves with slower defensive reflexes (and slower legs for Hagler). Hagler was a skilled boxer/puncher with good movement and defense for most of his career, and GGG wasn’t bad defensively either. Hagler generally liked guys who came forward, where he could catch him with the jab and open up with combos, and use good lateral movement. He was a very accurate puncher. GGG had an excellent jab and was a very effective counter puncher in his aggression. It would be a good technical fight punctuated with some excellent exchanges. Hagler wins a 8-4 type decision
The only 2 fighters relevant were Ward and Canelo. Ward did offer him a fight in 2015 but it never went through. Ward was never scared to fight anyone. You can argue that Canelo grew some balls after GGG fought Jacobs. Fighting Eubank, Sturm and Cotto would have meant zilch.
Do you watch fighters that you aren't a fan of? Hagler's jab was much longer and was faster than GGG's. He used his legs better than any fighter that GGG faced and that powerful southpaw jab was a piston and would bang him up because GGG has no head movement.
For example Errol Spence weighs in at 147lbs and comes into the ring at like 160lbs and is ripped, it is not fat what they put on after the weigh in, it is the water which they have drained from themselves which they put back on and Hagler would be able to get down to 147 by losing water weight then drinking water after the weigh in and getting back up to like 158lbs