I acknowledge there is some humor to that response but truth is GGG does stand an excellent chance to " Take him out late", in the actual fight. Hagler would take lots of punishment and like he did in the Hearns fight, get busted up with cuts etc. Even cuts aside, GGG vs Hagler would be a great fight between great middleweights.
They will never be resolved satisfactorily because they are from different eras and will never face each other. The common knock on GGG's resume is that he didn't face the level of fighters Hagler did. So I say, take this approach to that, what fighters did Hagler beat that GGG wouldn't figure to beat. Obviously that will also never be resolved but GGG would probably beat those guys.
Ac Actually if they were to have fought, Hagler would not have taken the same frequency of punishment that he did against Tommy because prime Hags was more of an aggressive boxer puncher type that utilized excellent footwork as part of his defence. Against Tommy, a past prime Hagler was quite aware that Tommy couldn't take his heavy pressure so he gave Tommy no space whatsoever. I also don't believe any middleweight in history knocks Hags out.
On a side bar, I believe Tommy boxes Canelo's head off, quite realistically stopping him late on cuts.
Hagler either bends the knee like Canelo, and plays eloosey goosey for a slightly possible points win, or he gets knocked out and damaged badly.
You levitate me Clinton Well I can't pick bones over anyone choosing Hagler. It's a dream megafight at MW, and a ridiculously good matchup.