Hopkins was the natrually bigger man. Hagler was more compact, but weight, height and length all belong to Hopkins thus making him the bigger guy.
Hagler struggled to dictate a fight to a blown up Duran, who's lateral movements limited Marvin's opportunities. Hopkins possesses that same skill, but also commanded a far more natrual swiftness of foot as his peak.
Where is the proof that Hagler is stronger than Hopkins? Because his muscles looked shinier?
Give me some proof man. Do you think Hagler has the same understanding of positioning and foot placement as Hopkins does? THAT stops him from dictating the fight to Nard. Hagler is not the ring general in this fight.
Who the hell ever walked Hopkins down? If he hits Hagler, Marvin will stop and take note, it's just a fact of life. If a 180lb man punches you in the face, you feel it.
Younger Hopkins (As opposed to the current version that I think you're using) was also much more offensively efficient, and would work both to Hagler's rib cage and head. God forbid Marvin turns southpaw, in which case he loses a lop sided UD, as maybe no better fighter in history has existed as Hopkins, when it comes to left handed opponents.