Ali was the man who gave a 12 round fight a deeper strategy. the fight against foreman for example... how to win against a hard puncher like foreman for example? Sugar Ray Leonard, Lennox Lewis, Mayweather and co evolved this to modern era. While Ali took many punishment, Mayweather doesnt took any relevant punishment. But a heavyweight would have a harder time to fight in mayweather strategy wich works at lower weight classes best.