You beat me to it. I was going to note that prime Tyson certainly had enormous power but it was the power combined with the speed and technique and timing ... man, the young Tyson was such a well-schooled fighter ... that made him so deadly, not just brute force power.
I would put Golovkin's power in the same bracket as Hagler's both can consistently punch hard and both are very sharp with their punches. But I don't think Golovkin has that scary one punch KO power like some of the more notable KO artists at the weight.
1. Hasim Rahman. His reputation of being a big puncher is based on his one-punch KO over ATG Lennox Lewis, but in all the others fights his power didn't look devastating at all. Yes, he stopped Sanders and Meehan but he landed a million of power punches on their chins and both were still stopped standing. And Rahman couldn't stop ancient Berbick (who was demolished by Tyson and Mercado in his prime), ancient Ferguson (demolished by Bowe in his prime), ancient Al Cole (who was demolished by Sanders years before), Obed Sullivan (KOed in few seconds by Tua, stopped by Grant, Vitali and even brutally KTFOED by Fres Oquendo), Monte Barrett (KOed by Wlad, Haye, even Valuev and Cliff Couser). On the top of that Rahman failed to drop or seriously hurt Oleg Maskaev who had grad A china chin, absolutely awful. I think Rahman had solid power but he was far from top punchers of his era like Ruddock or Morrison. Couple of levels below them. 2. Chris Arreola. Chris had ridiculously high KO% and when he met glass jawed opponents like Walker, Mitchell, Molina or Augustin it looked impressive. But it looked average against the fighters who had an ounce of durability.
My opinion that's more about Hagler's chin and defensive skills being at the very top or close to it in the history of the division than Mugabi's power being overrated. Eugene Hart, William Lee, Alan Minter, Fully Obejeimas, Tony Sibson Bennie Briscoe, Ray Seales, Bobby Watts, Juan Roldan, of course Thomas Hearns, all had the reputation of very good, to murderous punchers. Yet none, not one seemed to seriously hurt Hagler. Hearns hurt him for about five seconds, then Hagler damn near killed him. And to put it into perspective , Hearns very next fight after Hagler, he obliterates and up and coming undefeated and was seen as the next middleweight champion James Shuler with one shot!!!! For you size worshippers Shuler was a big middleweight, about the build of Gerald McCellean and looked like he could jump to Lt.heavy without any issues. But one clean shot from Hearns, in the very 1st rd. He's gone. Hagler was simply the best I've seen other than of Muhammed Ali for absorbing a tremendous punches. Hell , Ali was hurt more often than Hagler was. Also again my opinion, Hagler ruined Mugabi. He never demonstrated the fire he showed against Hagler or James Green again. Hagler took the fight out of him. Even in his wins he never looked the same.
Comeback George Foreman. He failed to stop a single fighter with good durability and failed against several with poor durability.
Now back on topic overrated punchers Look no farther than Gerald McCellean. If you look at his resume you will notice almost everyone of the men he faced were fringe contenders at the most. (Unlike John Mugabi's opponents prior to Hagler though nothing great, they at the least were known as tough guys. Men he had to beat, they were not going to just lay down, his run through the legendary Philly and Jersey middleweights were almost as impressive as Hagler's) Yet McCellaen has this rep as a murderous puncher. His best opponents were a broken and koed multiple times prior to fighting him, John Mugabi and a past past prime smallish natural Jr.middleweight Julian Jackson. He landed every power shot conceivable on Nigel Benn for 10 rds. And yet at the end he was the one stopped. Benn was stopped twice by relatively light punchers before he fought McCellean and he was never seen as a fighter with a great chin. The poster child for this subject is Gerald McCellean my opinion....
I do think that his power was a tad more than just "a punch", personally. He staggered Holmes pretty badly in their match, and I think that his biggest issue was that he often didn't capitalize on the natural power he had.
No doubt, the Hagler/Mugabi fight was brutal and probably took a toll on both men especially Mugabi. Mugabi was a heavy hitter no doubt, but against other top fighter's post Hagler fight, he simply wasn't the beast that he was pre Hagler. I agree that Hagler simply had an atg chin but Mugabi's power never really translated in other fights with high profile opponents. I just think too much was made of his power and at the end if the day, that power wasn't the same against his higher level opponents.
I understand your point. But as you wrote it was post Hagler. Hagler simply broke his will and intensity. in a sport that's 95% mental. Many big punchers suffered the same fate after their first defeat. Foreman after Ali , Cooney after Holmes, Garza after Meza, many others......
Rahman had a really hard jab, which gets forgotten. I always saw Arreola as a combo puncher, not a one shot ko artist.
Yes, Rahman had a good jab. He just wasn't a monstrous puncher as some people say he was based solely on Lewis KO. But yes, his jab was good. It was a key factor for his success against Lewis. Surely, Lennox wasn't focused in that fight but I'm sure that guys like say David Izon, who had no jab, wouldn't be able to set up right hand like Rahman did against any version of Lennox
I actually think he did have huge power. He delivered it with minimal feinting and limited handspeed though, so he was better off throwing at 70-80% at top level, which he did. I’m pretty sure there are highlights of him putting cab drivers into orbit on the way up.