Like you I rate Lewis's title reign very highly, but I think one observation should be made. He tended to fight the opponent that the media wanted him to figh , or the one who brought the biggest payday, but he seems to have valued these factors above a fighters ranking.
That isnt the point, the point is are they better than the wins posted by the challengers you say Tucker beats? "I there's the rub."
If we're talking about quality of the challengers, Muhammad Ali's opposition takes quite a big knock because Liston and Foreman cannot be included. Who have we got left who's any good ? Ernie Terrell, Joe Frazier ('75 version), Folley? Patterson ('65 version)?? throw in Shavers because he could punch. Norton and Young ... but Ali probably should have lost those fights. And a load of bums, second-raters, has-beens or guys coming off losses. There are guys there you'd pick Alex Leapai to beat.
It is good that you did not include that bum Vitali or Wlad in the list of title reigns because their title reigns are worthless