I have a ton of fun using Nidalee, but I feel like mid-late game all I do is look for openings to hit spear, heal my allies and try to set traps up. I never feel like I can get in there in melee range and be of use. I probably need to get more comfortable with the cougar form.
Build Trinity Force and bruiser stuff. Cougar form. Pounce rawr rawr rawr.
Thoughts on KZ evolution path:
Evolve Q or W first for ganking.
Q if your lanes have decent CC.
W if your lanes don't.
Last evolution point for E for jumping on carries in teamfights. During laning phase I don't think the extended range and reset on kill is all that helpful.