You made Fizz rely on a BS ult to be not trash. And then nerf it instead of fixing the bigger issue.
New Fizz had literally nothing he can do except rely on a bullshit ultimate with a ridiculously large hitbox. Every time it's off cool down, he tries a shot at the carry. If it misses, he waits till next time ultimate is up. If it hits carry, he goes in to finish them off and hopefully doesn't get Exhausted and CC-murdered while the carry gets shielded/healed for 1500-2000 EHP.
But instead of fixing the flaw with this design which was the source of the problem, you make his ultimate not bullshit. Normally, this would be perfectly fine and reasonable. But this was literally new Fizz's one and only redeeming factor from being complete and utter garbage. And you touch nothing else.
This reminds me of when Azir's E bonus HP scaling was bugged and not working. And instead of fixing it, Riot just removed it altogether.
F for eFFort.