the way it is used, there is no such thing as a stat check(otherwise we would all pick the champions with the currently highest, easily available statistic), but there are such things as kit-checks
for example, if dr mundo lands every cleaver and wins, despite being weak, does that mean he stat checked his opponent?
dr mundo is tough and can keep outputting damage. That is all he has going for him. Unless the mundo plays well and evaluates what situations require and what he can do, he can't do much. Just running in is a terrible idea because the plethora of available champions can do everything he can and more, so, naturally champions with less options need higher stats in order to compete. You don't overdo it, but you don't make the game better by forcing change
dr mundo scales with items, as does every champion that requires bulk to function in a reasonable manner
in fact, the higher divisions go, the more HORRID his winrate becomes. In diamond and above worldwide, he's currently sitting at a 45% win rate and 1% playrate https://www.leagueofgraphs.com/champions/overview/drmundo/diamond
and in other divisions, he doesn't break above 48%
I could design a super-awesome kit for him to bring him up to modern standards, but then he probably wouldn't be the champion the players know and love because his gameplay is derived from extremes and typically, the more awesome the kit is, the more it has to be nerfed to bring it down to the level of other kits, and that's coming from an idea that's mostly just remaking his current abilities to keep his current identity