I also main Nidalee Mid. I have been taking her jungle since the new update with the rooting, and... it's amazing. However, I strongly believe that she is only OP in the jungle when the person knows how to play nid well. We all know landing the spear is really important, and what makes her jungle strong is the ganks, and landing the spears. I think a lot of nid mains are trying out the jungle, and contributing to the higher rates. The most people see good Nidalees do this, the more other people will try, and not do as good. She is not a hard champ to play, but to play her well does take a bit of skill.
I also fear an incomming nerf, because Riot loves to ruin champs that I play, and I LOVE her kit currently. Playing her jungle is SO MUCH FUN. I Main Mid, and Jungel second. I play very few champs jungle because its not as viable as last season. Nid jungle is a breath of fresh air. Every game is exciting and I just want to play more and more.
If they must nerf her, I also hope its just a minor nerf to her jungle. If they nerf spear damage, or cougar damage, Im not going to be happy because Mid lane she is PERFECT at the moment, IMO.
Her jungle clear can be iffy, just because the monsters sometimes turn away and regen life, and its really glitchy when that happens. I dont think reducing her jungle damage to MONSTERS will have a giant impact, because the issue is her insane ganking and mobility in the jungle (which of course is what makes it fun...)
I wish the pros didn't take her jungle, and she could be left under the radar and leave poor nid alone :(