Kai'Sa's Nerf might be too heavy

I get the idea behind the nerf was to eliminate her as a tank killer when building AP. That is understandable since she already has good damage vs squishy targets in the late game plus a lot of defensive tools to use (items included). However, there is a significant issue here which could make her unplayable, or at least lack a reason to play her over any other marksmen. That is her build and its relation to her abilities.

She has a lot of options build wise. This is because she has 3 of 5 abilities scale both AD and AP. However, when it comes to her damage, AP is currently by far better, having 4/5 abilities scale with it. Of her 3 damage abilities, 2 deal magic damage. And the third one which deals physical damage scales a higher percentage with AP. Her kit rewards her far more for building AP than AD.

Item wise, she will have a very expensive build, however she builds. Because she needs a few items to get her upgraded abilities, her strength comes later than most ADCs. Building AP helped this out a bit because it was a cheaper build path than building AD. She is not a normal marksmen like a Jinx, Ashe, or Tristana where your damage is 80% in your AA with one ability which has hard CC. However she would become one if forced to build AD. Thing is, why play her as a full AD, AA marksmen when others do that already and better than she can? You play her for her burst. A bad early game for a strong late. becoming an assassin for squishy targets after 3-4 items. You will not get this with her kit building AD.

Building AD to be a tank killer is a stupid reason to play Kai'Sa. Play Vayne if you want that, she deals % health true damage 2 AA before Kai'Sa gets her % health "burst". Kai'Sa building AD to be a tank shredder simply becomes a worse Vayne. Vayne does everything AD Kai'Sa can do and does it better. She has more frequent invisibility and mobility, and % health damage quicker in the 1v1. Not to mention her base stats are better too.

If you want to bring AD Kai'Sa back into play, then she will need more AD scalings somewhere within her kit, or increase her already existing ones to compensate.