Tyson has the most power. Witherspoon would be a close 2nd, though. Morrison is not a pressure fighter.
Many of these are not what I would call pressure fighters. I would pick Frazier over the field here, if forced to pick I think Rocky has the best chance of beating him.
All of them would have a chance. But honestly i don't really see a huge favorite in theese constellations. Most of them are 50-50 for me. I guess Frazier will have a slightly edge over Witherspoon, Povetkin and Norton. Norton not sytlewise, but because of his glass jaw. I saw some sparring montage and Ken outboxed him pretty well. Although i don't think you can compare that to a real fight. But if Norton survives the first 3 Rounds he will have a fair chance. Because Joe is rather a slow starter; Tua, Tyson, Dempsey are likely to catch Frazier in the first 2 rounds and may hurt him bad or even finish him. They are really able to explode right from the start. Plus i don't think Frazier can handle Tysons speed very well. I see a lot of trouble with Rocky...he has even more stamina and toughness than Joe. And he has power in both hands (like Tyson and Dempsey as well). I don't watched many Brewster and Ruiz fights yet. But i think Frazior has the edge over Brewster. Ruiz I can't really evaluate well yet. He could be troublesome in terms of style...also because of his speed. Basically I think Joe will have an easier time with oustide (boxers) than with punchers and pressure fighters. Guys like Ellis, Ali, Holmes, Page, Tillis, C. Williams... I think a Frazier would have really cleaned up in the 80s...until Tyson.
I'd make Tyson a slight favourite over Joe. Rocky a 50-50 I think Joe beats the rest of the list. (Dark horse: Povetkin)
Both Tyson and Marciano fan beat him, but I don't think they would. I don't give others much of a chance, at all.
Frazer had mixed results against big, strong fighters. Even at his best big (Mathis), strong (Bonavena) gave him problems. Against some of the fighters listed, he'd probably not do well based on past results. Tyson is too strong, puts hard punches together too quick, it wouldn't last long. Might almost look like Tyson vs. Marvis Frazier. Tua could also blow out Frazier if he fought him like he fought Ibeabuchi, Moorer, and Ruiz, if he was lazy, Frazier would decision him. Povetkin is a two handed, highly skilled inside fighter who is much bigger and stronger than Frazier. People forget that Povetkin is 6-2, 225-30 because he usually fights people even bigger than himself. He'd have all the physical advantages against Frazier and he has the inside skills. Frazier was also an Olympic champion with good inside skills, but Povetkin is bigger and stronger and as/more skilled on the inside. Brewster would also have a good chance. Good fighter with a big left hook. Again, Brewster is bigger and stronger. Ruiz is not really the same type fighter as Frazier, he fights at all ranges, more of a Holyfield type. Ruiz in good shape would have an excellent chance of beating Frazier. Ruiz is quick handed and skilled, conditioning is his biggest weakness and since these fights are best vs. best, he would be in his best condition. Frazier had problems with Buster Mathis, who was a fat 240ish fighter, Frazier won but it was not a blow out. Bugner, was a decisive win, but Frazier didn't stop him. The only other bigger (215+) fighters I can think of that Frazier fought were Ali and Foreman. Another would be Jumbo Cummings...Frazier seemed to struggle with strong people, even Bonavena who wasn't that big. He did well with the below 200 pounders like Quarry, Ellis, Jones, etc.
Tyson for me, he had the power tohurt Frazier quickly. Joe was a slow starting fella, he'd be caught out fast as he was with George.
Tyson was a real quick starter, he's the only one I'd pick to stop Joe. Marciano? don't see it, a smaller man attacking Joe Frazier ain't working. Dempsey would be interesting ,he'd have to get Joe outta there quick or he's in trouble
Quarry fought like Morrison and Povetkin and Norton wasn`t more of a pressure fighter than Quarry either.
He couldn`t take Tyson`s power, plus Mike wa better at landing power shots than anybody Frazier fought and a better finisher than anybody he beat.
Frazier was better at landing hooks than Ike, and would have destroyed Ruiz and Moorer, neither of them were near Frazier`s level and Moorer had a weak chin.
I’d make him a favorite against all but Tyson. People often go on about his weaknesses against punchers, but the Foreman stoppage was far more of a Willard /Dempsey situation than a Graham /Jackson situation. Against lesser fighters, I can imagine him getting badly rocked, regrouping and turning the tide, especially if we’re basing this on the FOTC version. Tyson’s finishing skills is what separates him here, though I’m not envisioning a quick blowout. I can see it resembling the Jesse Ferguson fight a bit with Frazier crowding and making it an ugly, awkward fight, limiting Tyson's leverage, until Tyson finds home for a crushing uppercut and follows up with a furious assault.