you are still not understanding the argument
leesin: high skill champion right? therefore he should have a lower winrate by his high playrate, FEWER PEOPLE SHOULD FIND SUCCESS WITH HIM. because fewer people are simply good enough, this is why his ult was nerfed. because he was too powerful even in the hands of a inexperienced person
vayne: VERY high skill cap champion, should BY DESIGN have a lower winrate then most other champions by her playrate. having a high playrate is fine, that means the community is trying her out, but i dont expect every one of them to be gosu, if she is having a high playrate AND a even DECENT winrate, that means something is wrong, there is some level of abuse or a bug or a imbalance in that champion. there is no reason why half the adcs should be playing her in every game, and winning half the games she is played. when champions are literally pick and ban there is a problem here and it needs to be fixed.
a 50 % playrate on a champion isnt BY ITSELF unhealthy, like say if janna had a 50% playrate, its not too hard to imagine, she is simple, easy, nothing real flashy about her, easy to find success with even with initial experience. alot of people playing her is normal, and jannas win rate has always been in a good place
now take a high skill cap champion like ryze, this man has a low playrate, and a ABSOLUTELY ABYSMAL initial winrate, way below 40%, but he has a monstrously high win rate by playrate, this is because he has a high skill cap when it comes to combos, and with how hard he is to play it makes it hard for anyone to simply pick him up and win with him