Well, I don't know. We know Tyson lost to a fat, chronically diabetic boxer named Buster Douglas who was unceremoniously K.O'ed by a steroided infested, bulked up cruiserweight Evander Holyfield in his very next fight. If you want to find a great heavyweight who could defeat the Klitschko's look no further than Lennox Lewis. He was a true huge heavyweight boxer with a terrific skillset and great fluidity for such a big man. Most other heavy's outside of Holmes would wilt against the two-fisted power and awesome boxing technique of the Ukrainian brothers.
Tyson would be favored in all the fights, but he'd blow a couple along the way like Wlad, and pretty much every HW does at some point. If it were that easy to go 55-0 fighting top 10 contenders and champs at the HW level, we'd have seen it by now.
And your point is ? Lemmie got iced twice by ham and eggers with one shot and he did not look particular impressive in both fights while they lasted.