And her Ultimate being on a 90 Second Cooldown is the biggest issue no one wants to talk about. Honestly, I am used to be nuke ultimates. Obvious this one is pretty extreme but I am willing to accept it (if not at least see a bit of a nerf to it). No, the real problem is her very powerful ultimate can get as low as 54 seconds (I may be off by a couple of seconds). An ultimate this powerful should be on a longer cooldown to balance it out.
And for those crying about her ratios I would like to remind you that Ekko deals 150/300/450 (+150% Ability Power) magic damage to nearby enemies on his ultimate and gets 100/150/200 (+60% Ability Power), increased by 3% for each 1% of his health lost over the last 4 seconds health back. Yet no one is crying out against that. Or how about Vel'Koz with his 450/625/800 (+125% Ability Power) damage on his ultimate. Yeah its over 2.5 seconds but it also is an aoe that slows and can deal true damage meaning it can do even MORE damage. And there is many others like this.
Now i am not saying its perfectly okay but I'll be real. Her cooldowns are the biggest issue with Neeko. They allow her to keep using her abilities way sooner than her burst should be allowed. But thats just my opinion as someone who has been playing her and playing against her a lot. Cooldowns across the board should see some increases.
EDIT: I forgot to mention her Root is pretty dumb. Early game its a 1.8 second up to 3 second root that only needs you to hit at least 2 minions. That is something I think people are not talking about enough. This is why her trades in lane can be so powerful.