Ahri and Nidalee are NOT balanced
Ahri was fine before DFG was removed, it was possible to opt out of building dfg and still do well. Giving her a movement boost, more damage, a faster targeting system for W, was certainly NOT okay. She currently has a 57.68% winrate, and has everything a champion wants in the current meta - mobility, sustain, good scaling, and TRUE damage to top it all off. Ahri is an extremely forgiving champion to play, and if she builds Rylais she just becomes even more a nuisance to deal with. Finally, she has no meaningful weaknesses.
Nidalee was already on the strong side before the pretty random addition (to me) for her to now have the ability to mark jungle creeps as hunted. She already does just as much damage from before the rework, albeit at a slightly higher risk.
TLDR: Stop giving champions that already have a strong kit even more just because it looks cool. There are a huge amount of champions that need that attention, Ahri and Nidalee were the farthest you could get from that.