One thing I hate about Riot is that they simply nerf champs in random ways. What I don't understand is why this is always approach #1, instead of identifying what makes the champion problematic and addressing that.
Look at Yorick. His early game is really strong so theyve nerfed him into mediocrity, but killed his mid to lategame. I dont even see him on dominion anymore.
To fix, Kass they have to identify the actual problem which is his Mobility thru his Ult. That he can jump in, burst,then escape.
Or play Pooters style and be uncatchable.
Even if trapped the fast CD ult makes him very hard to kill.
Riot has nerfed various parts about him but failed to fix the actual issue.
To be honest, AHRI is the "fixed Kass" in many ways due to how her ult works.
How bout simply increase his Ult Cooldown to 20 sec or so? Now he can use it to initiate OR retreat but not both, and not be able to escape multiple times. He wouldn't be as mobile as Ahri but he wouldnt have excessively long CD when he is extremely vulnerable either.
In exchange he can get quite a few BUFFS. Theyd remove the increasing cost of Ult and raise its damage and AP ratio. This way if he uses it as an engagement, his overall burst is harder.
They can increase its range a bit so he retains his "surprise!" mobility, but cannot simply hunt down someone to the ends of the earth.
Re-buff his Q range and damage.
It ought to work for SR and TT as well. Still has great mobility but simply cannot spam it all day long. Increased burst and ratios would make him even stronger at engaging and ganking at the cost of no-escape. Or engage like normal and save teh Ult for escape.
It would change his playstyle to not necessarily be so mana-focused, and play more like KZ.