Vayne is supposed to be a high skill floor champion with high-risk/high-reward gameplay...
Yet, she is almost in 1/4th of all the games and has a winrate thats way too high for a difficult champion. Her previous buff was unneeded and way over the top and the crit changes were also an indirect way to make her even stronger, to the point she is getting more and more picked top with an also pretty high winrate since noboddy really can compete with how powercrept she became. You can't deny it; she became a blatant problem for the game balance in every elo, even in low, and she needs some well deserved nerfs, no matter how you think about it.