Patch 9.18 Hurt Kai'Sa
Comparing 9.18 with the previous patches, 
's performance is majorly affected:
Lolalytics:
9.18: 48.84% overall winrate, 53.9% best winrate. 9.17: 49.36% overall winrate, 58.1% best winrate.
U.gg
9.18: 48.85% winrate at 38.2% pickrate in Master+ 9.17: 50.1% winrate at 42.5% pickrate in Master+
Why is that?
I'd argue it is because Riot did what the Boards and Reddit always ask them to do this time: Instead of majorly nerfing the champion directly, they gave Kai'Sa a small nerf to her AS on E while buffing up champions that counter her, like 
. If that's the case, then her performance should continue to get worse as 9.19 is released (with buffs to 
and 
).
