She brings nothing of value to the game, has no new mechanics, and is just a mash up of random void champs packaged into a braindead, no counterplay statcheck that goes against many of the "rules" Riot has talked about as far as balance goes.
So can anyone explain to me what reason Kai'sa has to exist, other than to sell skins to morons who see a pretty girl? I'd be impressed if you can find one.
Champions I consider mistakes.
AP
Just an Ad version of never can seem to get 
right 
(Not sure why he has kennens stun when he uses kennens ulti the stun is on kennens passive not in his ulti.)
Cant beat him past lvl 9
Same problem with vlad a double passive.
Needs no explaining.
Antifun throws sleepy bubbles every 8 seconds from behind wall and fog of war and 1 shots you.
Problem is other ADC champions have very dull gameplay for currently meta not mainly Kai'Sa she is real aspect of an ADC champion that how should be now. She is actually so fun to play because pretty much reminds me Wind Ranger from Dota 2. :)
No but she brings in the cash so...
She's a fun adc that has a relatively unique build and playstyle
I partly agree, but I wanted to add that I wish people would stop using "brain dead" as a term. It is essentially meaningless, what is hard for one person is easy for another.
For example, I'm not as good at twitch reflex mechanical play, but I'm good at macro play and positioning. For some people those reflex mechanical plays are easy, but they suck at objective control and paying attention to the map. That doesn't make one of us "brain dead" we just have different skills.
This is true for champions too. Some kits need to be simple and making them more complex is not an improvement. Particularly if that champion exists as a counter (such as Rammus or Malphite), you could make those champions more complicated, but then picking them as a counter would be pointless because you wouldn't be able to play them. It's important champions are accessible, and that not everything have a really high skill ceiling.
Many high skill ceiling champions have also historically been worse for the game and game balance such as Azir and the new Akali. At least for me, I also prefer older champions who are easier to use and have meaningful windows of power up and down vs. something like a Sylas with really low cool downs who never has any openings.
Just my two cents on the matter, take it or leave it.
