The Xayah nerf on PBE is absolutely savage for a first nerf.

After this nerf her W will be close to the worst spell in the game. Xayah currently maxes it second but after the nerf all you gain is 5% AS per point going from 30% AS to 50% and the spell has 20 seconds cooldown and only 4 seconds of up time.

Tristana Q is a 16 seconds Cooldown with 7 seconds up time. 110% AS.

Realistically this is more than a little overkill for a nerf considering her Q is pretty lackluster mid/late game. Her winrate sits around 50% with a moderate pick rate already.