I know that Marvin wins.... but how awesome of a fight would this have been while it lasted? the bombs that would be thrown would be a sight to behold.
Hagler has the strongest chin in boxing history (never been floored), so forget him getting stopped because he was never even floored in his career. Hagler has two different styles that he uses depending on who he's fighting: he can brawl and swarm you, or he can just outbox you. Since he outbrawled Tommy Hearns and John "The Beast" Mugabi, we can rule out that Abraham would hurt him. Since he outboxed Sugar Ray Leonard and Roberto Duran, we can also assume that Abraham would never outsmart him. Marvin Hagler is simply the greatest p4p fighter who ever lived. There is no way to get past him. He beat every man put in front of him, and ducked no one.
Abraham would get outworked. Hagler can fight in his usual boxer-puncher style, or take it to Abe and beat him on the inside. Abe shelling up and throwing a bomb every eon won't work against a great fighter like Hagler, who had effective parrying/head movement and more than took a good shot when he did get tagged.
And if AA was able to take his face out of his gloves at some point during this fight he might behold some of them.
Hagler would win every single round by fighting on the inside, taking a wide decision or more likely getting a late stoppage. Totally different category of athlete.
This monumental ass whoopin' would be the quintessential example of our beloved saying "styles make fights." Martinez, Pavlik, Sturm, Pirog, and Taylor would all lose to Haglar, but they would all do better than Abraham. A somewhat limited Carl Froch used a basic boxer/puncher style to beat the brakes off Abraham. Now, take Froch out of the picture, and insert the premier boxer/puncher of the modern era. There's you answer.
This would get ugly. Abraham wouldn't be able to do anything effective and Hagler would not only make a fool out of him, but seriously beat him down.
If you think non-competitiveness makes an awesome fight, then it would be awesome. It might be an awesome boxing clinic...but not "fight". Incidentally, you've probably just made Boo's day.
A: Not very awesome at all, unless you really hate Abraham or like seeing things come easy to Hagler. Abraham is a very slow starter and always gets shy when confronted with aggressive pressure. Before it ever reached the rounds where Abraham usually starts getting himself warmed up, he'd have already been stopped. The bombs Hagler threw - and smashed his way through that high guard with - would indeed have been a sight to behold.
The only questions are how Hagler wins (decision or stoppage), and in what style he fights (usual boxer mode or the aggressive animal that took out Hearns).
I think if Hagler had ever seen Abraham fight before this hypothetical match-up or received even minimal scouting, the answer to both questions would be the latter answer.