I have a confession to make about Nidalee.
I suck.
I almost got executed the first time this season when I tried to take Gromp. I played at least 15 custom games (each one ending when I cleared all camps), and I still feel really useless with her. I have to use tanky-ish masteries so I don't kill myself. I try to kite and switch between her two forms like you're supposed to, but damn it's much more intricate than a jungler with only one form.
I started playing her again in S6 because... the snow leopard skin was available. I am a SHAMEFUL summoner. The skin is the only reason I resumed playing her. However, I realized that she's actually really fun to learn. I mean, sure, it may not be fun for my teammate when I fail a gank... but you get the point.
So if you feel as if she's OP, I encourage you to play her and find her weaknesses. Yes, there are many.