Tyson's defense are rated about right IMO. The extremly underrated thing about him was his stamina, in his prime he was no Frazier or Marciano but it was certainly better than foreman's and Morrison's
Joey Archer and Sven Ottke. Both of those guys were excellent outside fighters that had an understanding of dictating range. What the lacked in power they more than made up for in ring IQ and defensive ability. Neither man was ever knocked out and were very rarely hurt.
Roberto Duran (though I think most people now acknowledge how beautiful his defense was) Sugar Ray Robinson and Joe Louis - they were very attacking but their defense was obviously also really good and embedded into their attack so that it's not so immediately noticeable. SRR used his footwork and athleticism more whereas Joe Louis parried very well and his textbook stance put him away from most danger. Jake La Motta Henry Armstrong Basically a lot of offensive minded boxers are type cast and their defensive nuances go under the radar
Universal Classic Rule: If your favourite fighter is not known for their defence, they have an underrated defence.
Benn got hit a lot more at 160 than at 168, Eubank hit Benn a lot more in their first fight than in their rematch.
Interesting to hear Chuvalo more or less imply that his own D was underrated - stating that he was mindful to keep his chin tucked and avoid punches to his vital points. I dunno. I’m not so sure I saw George execute this “subtle” D. While it might’ve been flattering to be afforded a great chin I think George might not have liked the idea of his being viewed as an immovable punching bag - so he wanted to insert some defensive “skill” into the equation.
Ironically, Jack Johnson’s D was a bit overrated but might now be underrated. We see on film how much he held but I still think he employed a number of otherwise legit manoeuvres to avoid being hit. Of course he wasn’t dealing with multi punch combos coming at him so there’s a question mark as to how successful he would be against same. However he seemed to possess the fundamental and inborn, nuanced defensive abilities exhibited by great defensive fighters. Against mods. Johnson would definitely have to up the effort on his D in open fighting (eg - keep the hands up more, etc.) it’s all guess work but I think Jack had it in him to up the ante on his D in the face of greater offence and perhaps also understand that upping his own offence would constitute itself as an addition to his overall D also.