Yasuo suffers fro mthe same thing Leblanc and Vayne suffer from

Basically it comes down to when being played well he is just to oppressive especially in some situations.

This in turn is why he is too strong.

Think of Leblanc when she had her silence. She was not that much above a 50% win rate but when someone was good with her they could easily carry the game on their own. And the last Leblanc nerfs happened when she was at a 48% win rate if you are going to be going of f that.

THis is why Yasuo is in turn too strong being at a 49% win rate.