I think Holyfield would have given Ali Hell based on his style, Lennox, Vitali, Wlad based on size and athletic ability. Chris Byrd would have been difficult for Ali. Riddick Bowe may have been tough for him. Larry Holmes would always be tough for him. It's a style matchup that doesn't suit Tyson is all...Mike Tyson was great going forwards, well Ali was just as great going backwards, if you're a big puncher, if you're a pressure fighter you're going to be a Bull chasing a Matador the entire fight and Ali had the speed and skills to avoid Tyson's power. Ali's chin, his ability to recover, his ability to use his speed AS his power...that doesn't work well vs what Tyson did well.