~~~~~~~~~~~~~~~~ Clearing up EVERY misconception on Nidalee, from a Diamond player ~~~~~~~~~~~~~~~~~
To start. Everyone seems to hate the character and I don't get why. It's mostly based on inferiority complexes in addition to sexism. But nevermind that.
Nidalee's Q (the spear) is perfectly balanced. Many think it isn't, it only isn't when the skin of some of the Nidalees is in play; because the spear colour is a bit imbalancedly difficult to see. Other than that, it is very balanced because of many reasons you probably wouldn't understand if I typed here (AND ESPECIALLY...since the Width reduction in the update!)
Nidalee's Bushwack Trap IS unbalanced because of the fact that the 3D model for the graphic is smaller than the affection radius of it I believe. To those of you from nob town, it's meaning you'll take damage or whatever from it without actually clicking your character onto the graphic (stepping on it).
The Primal Surge (E) can be viewed as imbalanced because it heals too much if built correctly, but it isn't when you look at the other characters. In addition to the fact it remains too much of a health recovery when you're one of those abnormally good players at the game. Which thankfully, is a small list! So safe to say, it won't be a problem usually. No offense! xD
The ult of Nidalee used to be only aquireable at Level 6. That generally meant more back in the day as it gave her a reason to reach level 6 like the other characters. Ever since then, it HAS changed it a lot. But not in a way that makes her too imbalanced.
If anything, it's the change of her ult form's Abilities. They used to be purely Attack Damage-dependent, now they use AP too I think. And the mark thing on the opponent that speeds you up CAN be viewed as imbalanced; but again it's fun and only really useable when you are good at the game. As in when really good, you'll see that it CAN be too easy...but that's probably because the other player isn't using their character as well!
Hope that cleared it up!