When comparing fighters you cannot compare Ali to any other heavyweight.
He is unique. No other fighter in that weight class could move the way he did or punch so fast. We need to compare Ali to middleweights and the other lighter divisions to find another similar fighter.
The first obvious one is Sugar Ray Robinson
The second, more modern example is Roy Jones Jr
Both these fighters had style and class and, like Ali, were real showmen.
RJJ used to taunt his opponents, dominating mentally as well as physically.
And in many ways RJJ like is a lighter Tyson.