I've been seeing a lot of discussions on Nidalee these times, and I wanted to share and discuss my thoughts on her. Wall of text incoming.
First of all, I'm a Nidalee fan. I wanted to buy her since the moment I started LoL, and I mained her since I did buy her. I don't consider myself a very good player, but when it comes to Nidalee, I know what I'm talking about. Also, note that this is about AP Nid, since she's the one people complains about.
Of course, all of this is my opinion, you are free to disagree.
So, as I said, I've been thinking a lot about her, and I wanted to share my "analysis" of her skills, in terms of efficiency, coherence with her theme, and fun vs anti fun (this was inspired by this Zileas post I stumbled upon when reading comments on her page). So let's start.
Prowl gives Nidalee a small movement speed buff when moving through a bush. It's usefull without being broken, and it makes sense for a huntress that grew up in the jungle. In terms of fun, its rather discreet. I never thought "Wow, my passive just saved my life" as Nidalee, or "Without her passive I would have caught her" against her. It's a nice passive. Could it be something else? Eventually.
Human Q :
This is what most of the discussions are about. Thanks to this skill, Nidalee is an insane poker. Thanks to this skill, Nidalee can play extremely safe. Thanks to this skill, she can steal objectives or finish off fleeing enemies. Because of this skill, some people go the point of calling her gameplay toxic.
So. In terms of efficiency, this is what most people thinks about when you say Nidalee. It has a long range, low cooldown, moderate mana cost and very high damage if it can travel a bit. This is definitely one of Nidalee's most powerful skill, if not THE most powerful one. Even with the recent nerf that prevent the cougar + jump back trick to increase damage, and that makes the travel distance bonus occurs only once the spear got past Nida's attack range, it's still strongly advised to not be hit by one of these.
Does it makes sense? Yup, pretty much. Spear tossing is a pretty standard hunting move. Not much to say there.
Let's talk fun now. What's fun with this skill? Hitting a carry before a teamfight? Not so much, actually. Pre teamfight, landing a good spear will depend much more of your enemies' errors than your own skill. It doesn't really feel rewarding, because it's the enemy that screwed up, not you that played well. While for your enemy, it's a whole load of anti-fun, because if it's a carry that gets hit, it often means a 4v5 teamfight. Because of a single spammable skill. Hence why people call Nidalee's gameplay "toxic".
What is fun with this skill then? Sniping. Finishing off a fleeing, low-life enemy by tossing a single, well placed spear. Stealing objectives under the nose of enemies. This is what's fun with Javelin Toss, and it's all things that don't only depends on enemies' mistakes; you need to time it right to steal objectives, you need to predict the enemy path to finish them off. And these are things that you can do something about; proper warding will allow you to see Nidalee coming and prepare your smite. While fleeing, it's relatively easy to dodge the spear, or to have an ally protect you. Much more than in a pre teamfight situation where each team waits for a mistake to engage, where spears brings constant pressure.
Human W :
Allows Nidalee to put a trap on the ground. It's not the first thing you think about when you hear Nidalee, though it has certain advantages.
The traps last for quite a while, grant vision when cast, and there is no limit to their number, unlike Caitlynn's ones. When an enemy steps on them, it will deal reasonnable but still interesting damages and, more importantly, reveal them and apply an armor and mr shred. Though the duration was recently nerfed from 12 to 8 seconds, all things considered, it's still huge. And even at lvl 1, the shred is quite important, especially considering it affects both armor and mr. Sure, it cost a lot of mana, it has a little setup time and the traps are visible, allowing enemies to walk around them (or even turn them into mana pots for Sivir). But enemies are prone to steps on them at some point. And when they do, they are going to regret it. Even if you're not around, any ally will benefit greatly from the shred, and the reveal will warn about eventual ganks.
Is it fun? Not so much. The only time I was really happy about a trap was when it reduced an enemy mr low enough for me to literally one shot him with a spear. But I doubt he/she was happy. The rest of the time, it's a shred and a reveal. It's nice, but the fact that it's a trap reduce it's effectiveness in teamfights, where it would be the most useful. Most of the time, it's a facechecking/anti gank tool. If you put them on common jungler path and not only around your lane, you will rarely be around to benefit it. You may not even notice it if someone steps on one. The enemy, on the other hand, will have to deal with the pressure of beeing visible for 8 seconds. For a laner, it's not that problematic; you just have to take care of the shred. For the jungler, on the other hand, it means everyone knows where you are, avoid you if you were going to gank, or go all-in without fear if you're far away.
There is also the "makes a narrow escape with 10 hp, step on a trap and die" situation that, while it indeed feels nice to snatch a kill teemo-style, is probably very frustrating for the one that suffer from it; much more than with said rodent, because here the traps are both visibles and not very damaging.
It makes sense, for sure. A trap is a great tool for a hunter. Should it reveal and shred? We could expect something else from a trap; a snare immediatly comes to the mind. But then it would be the same as Caitlynn's ones. It's pretty hard to imagine why stepping on a trap would lower your armor and even your magic resist. Slows, snares, bleeding would make much more sense. Perhaps because the target is wounded, it's unable to defend properly?
Human E :
This skill is one of the things that makes support Nidalee possible. It's also very useful to AD bruiser Nidalee. It's a heal with a big attack speed steroid on the later levels.
Let's compare it with an emblematic heal : Soraka's's . It has a lower base, but higher AP ratio, even if we take Soraka's passive into account, and a lower mana cost. Considering that Nidalee will often have big amount of AP, this is actually one of the best heal in the game, though it's single target. And with that comes a pretty nice attack speed steroid that can do wonders when put on an ADC. It's also a very useful sustain tool through lane.
When it comes to fun... it's just a heal/a steroid. Sure, it feels nice to save an ally from the brink of death with it, or to turn your ADC into a war machine. But it's nothing more than that; "nice". For enemies, I can't really tell. As far as I'm concerned, it's a great way to force Nidalee to deplete her mana bar by harassing her and forcing her to heal, preventing her from putting traps everywhere/harass with spears non stop. In teamfight situations, spamming it along with spears will eventually deplete her mana, even with mana items.
However, it doesn't makes sense. The steroid, eventually, could; primal fury and stuff. For a bestial huntress, we can let it slip. But the heal? Where does it comes from? It feels like it's there for the sake of giving her sustain, and nothing more. As useful as I find this skill is, I need to admit that it just plain doesn't belong in her kit. Also, I'll add that maybe with the exception of dedicated supports (and I'm pretty sure she wasn't designed as one), I think that a champion should fully benefit from it's kit. Does AP Nidalee, on her own, benefits from the heal? Sure. The steroid? Not so much. Yes, it's really useful to AD Nidalee; but would AD Nidalee exists without that?
Transform Nidalee into a cougar, and grants her access to the rest of her kit. Not much to say other than it also gives her 20 movement speed, putting her on 355, the highest base speed of the game, on par with Yi and Pantheon, and makes her melee instead of ranged.
Cougar Q :
This, along with primal surge, is what makes AD Nidalee viable. It's an execution that can potentially be very powerful.
Even though you don't build AD on AP Nidalee, it scales with total AD, so it can be useful even when playing AP. It's also a very good last-hitting tool. The execution can allow it to do a lot of damage and finish off many opponents; it's also an attack reset, which is always useful.
It makes sense for a cougar to jump on its prey like that, and while not being the best part of her kit, it feels nice to use. I don't thinks it's anti fun to get hit by it either; as far as I'm concerned, it's not. Not much to say on this one.
Cougar W :
THIS is where all the fun of Nidalee is for me. It's a short, spammable jump. When somebody says Nidalee, this is what I think about.
It has very high number of use. It deals damage, it allows you to charge a tear, to reposition, to go faster, to jump over walls and to dodge skillshots. I think it's safe to say that all Nidalee players spam this, all the time.
It's a whole load of fun. Whether you use it to jump on an enemy, to escape by going over a thin wall or to dodge, it feels awesome. Even when you're simply derping around on the map, jumping everywhere is awesome. While it may be annoying for ennemies to see you get away like that, a lot of champions can do the same; and when it comes to jumping over wall, it's short range means you need to know exactly where you can go through and where you cannot; and if you fail, you die, so it evens things out. As for dodging, it's the same, a lot of champions can do the same.
It also makes sense. Cougar are feline, and jumping is natural for them. Nothing else to say.
Cougar E :
Another good skill, which gives Nidalee her pushing power as well as quite a lot of damages.
Extremely useful for farming, pushing and dealing AoE damages. It makes sense, and while fun to use, it's not specially anti fun for the enemies, because you need to be close to land it. That's all I have to say.
TL;DR : Her cougar kit is fine. The problem comes from her human kit.
One thing with Nidalee is the lack of synergy in her human kit. While, in cougar, the Pounce->Swipe->Takedown combo immediatly comes into mind, there isn't such things in her human form. Sure, you have the trap->spear, but it's so random that it barely feels like a synergy. The attack speed steroid doesn't help you much when playing AP (for Nidalee herself; of course it's going to help allies) and the heal, while being useful, feels out of place on a bestial huntress.
Another thing that bothers me is that, for someone that grew up in the jungle, she has close to no reminder about this -her passive, nothing more- and she certainly isn't a good jungler, at least pre 6. This is especially frustrating considering that Rengar and Udyr, both having affinities with bestiality and savagery like Nidalee, are jungler by essence. I'm fine with Nidalee being a mage -I love my AP Nidalee-, but I like it too when things make sense.
One thing that could be done would be removing the "distance ratio" on her Q and replacing it with an execution mechanism; therefore removing the "got hit by a spear, lost half of my life" situation while keeping the stealing of objectives and sniping of low health targets. I would also be very happy to have her cougar formc available at level 1. Right now it just feels unfair compared to Elise's that, in addition to having access to the other half of her kit earlier, has more benefits on her transform (movement speed, on hit magic damage and spiderlings, vs movement speed). Not only would this allow her to jungle, but it would also make her laning phase easier, allowing you to take power away from somewhere else.
All in all, I feel that the cougar is what Nidalee is all about, and Riot should push her more in that direction.
That's all for now, I may add things if something else comes to my mind.
PS : If I made any typo, I apologize, english is not my native language. Just tell me and I'll fix it!