Frazier because he fought better opposition. Louis would have his hands full against Ali & Foreman...
imagine the work Frazier would do to Galento's body does Marciano fight fotc Frazier or following a timeline is it thrilla Frazier, either way I think this is the best fight such a war Louis beats Foreman but Ali is more questionable
I say Louis because I don’t think Frazier was built for the kind of longevity that Was required for a reign like the one Louis had. Reversely I think a prime Louis could have beaten the rusty version of Ali who Frazier beat and all of Frazier’s victims as well. Foreman would be a tough fight but even if Louis fails he still likely does better than Frazier did
Well, Frazier went 1-4 against them, so I don't think Louis needs to do a lot to fare better than that...