Disagreed.

Great fighters have only one obligation: to win fights.

To win fights, one must protect their weaknesses by fighting in a way that he is most proficient in and maximizes his chance of winning.

If a fighter has a questionable chin but solid defence that prevents his opponent from landing a flush KO blow, then his weakness is a non-issue.

Roy Jones had a questionable chin but went 15 years without a real loss and won belts from middleweight to heavyweight. Anyone who says he isn't a great fighter is insane.