I think Yasuo got nerfed due to his excessive ban rate. champion.gg has him sitting at 61.27% ban rate. That's every 6/10 games. Camile has the highest ban rate in both top and JG (70%+) while Yasuo is second in Top and Mid. I would say that this nerf is an attempt to try and make people realize that Yasuo, who has win rates 50% and 49% respectably, is not a broken as the community makes him out to be. He has a 50% win rate. The reason why people ban him over champs like Kayl and MF using your examples is because Yasuo, facing a good one at least, is like playing against a Leblanc who is Diamond when you and silver or gold. He simply outplays you or you outplay him. He is running on Constant URF mode. E dash on minions is quite short with a 10 sec cd on a minion or monster or champion after he dashes through them. added with a double crit chance passive and a Q that scales off of attack speed with an ult that makes crits have bonus armor pen. People just don't want to face the wind, Because more often than not the wind knocks them over or does absolutely nothing.
You also mentioned Kayle. who has around a 53% win rate with a 2% play rate. Her win rate is probably so high due to the little play rate and them maybe being main of that champ.
MF on the other hand whose lethality build is admittedly quite good. Is almost completely countered by flash/ any free dash, Yasuo wind wall/ Braum wall, and hard CC her directly like stun or knock up. While yes League is a competitive game. The game is not balanced around your Elo most likely. MF has dramatic win rate loss in higher Elo I would imagine, due to how her main damage source (her ult) works.
TLDR: Yasuo nerfed cause ban rate too high IMO, Kayle and MF fairly balanced due to low play rates, countability, or both.
[slayer-jinx-catface]
