I was thinking more of Mercer level. But of the 90s, I'd definitely say that Lennox Lewis and Evander Holyfield were the best. Holmes and Tyson the best of the 80s.
Not a very solid case, I think. First of all we have to a solid case to completely disregard the loss to Douglas. Douglas doesn't have a very impressive record - the next best fighter he beat was probably McCall - and he beat the crap out of Mike. So we have to have a solid reason to believe that Mike didn't only have a bad night, but was nothing like himself at all. I know all the talk about how he didn't train a second and only partied, of course, but can't say I'm convinced he was in that poor shape. Second, who was the best he beat, if we consider the time he beat him? Likely Tucker or Spinks. And Tucker was a clear points win, but no real domination. Also, if we excuse away Tyson's loss to Douglas we have to take Tucker's excuse about his broken right hand into consideration. Tucker was doing very well when he said it happened. The Spinks win was very impressive, though, seeing what a demolition job it was. But, still, Spinks was 32 and had two years earlier lost to a 36-year old Holmes on most people's cards. I am not saying that it is out of the question that Tyson at his best was GOAT and that only poor lifestyle habits prevented him from showing it, but if we're looking at the above I certainly don't see a solid case. Golovkin has about as good a case, only slightly weaker at most, to be viewed as GOAT at MW. But you wouldn't call that case anything close to solid, would you?
I meant H2H. There's not a heavyweight who has yet existed that an argument couldn't be made of them losing to a peak Tyson.
Yeah, I know you meant h2h, but someone who's best beaten opponent could well be a Tucker with a broken hand and who lost devastatingly to Douglas in his physical prime, don't really have a solid case for being GOAT in a h2h sense as I see it. EDIT: Berbick also has a good case for being Tyson's best beaten opponent.
The why is just as important as the how. Plus, Tyson beat many opponents like Buster Douglas who could do what Douglas could do. It's not like Douglas showed anything new. That's what many believed that Spinks would fight Tyson, exactly like that. So it's not that any of Tyson's other opponents didn't have the ability or skill. Even though Douglas did well, it was more Tyson that lost the fight than Douglas winning it. It was really the same story with Louis/Schmeling the first time around. Louis just got back on the ball after his defeat.
With Louis we know that he could do much better than he did the first time. We don't know that with Tyson-Douglas. And I definitely think Douglas showed him several things previous opponents hadn't. I think that's clear when one watches the fight. Also let's not forget that Tyson was well beaten by Holy. He was past his prime but so was Evander. Had Tyson beaten a prime Holy with no fuss then you'd have more of a solid case for being h2h GOAT. But you probably would have to throw in Bowe or Lewis there as well to make it really solid. But he didn't and I don't think he would have.
When you get into it, Tyson's resume is actually strong, in some areas where it is perceived to be weak. For example he stacks up well against a lot of the other ATGs, in terms of number of ranked opponents beaten. His level of activity during his prime, offsets his relatively short prime. Also even when he was past his prime, he still kept knocking over contenders. He should have been a lot more than he was, but he still sits fairly comfortably among the ATGs!