I'd like to start with by informing you that I'm not an SJW and I don't agree with feminist ideology in general but when it comes to Kai'Sa and her skins in this game they have a point. She's really sexualized to insane levels (probably more than any other female champion in the game if you consider her story).
Most of her life she was fighting for survival among wasteland swallowed by the Void. Her first days in there she was eating rotten peaches and drinking dirty water. Then when she got her 2nd skin she was feeding on Void creatures. You're telling me during all these years she didn't get any scars? Her skin, hair and face look amazing even though she dwelled in darkness for years? She had time and concerned herself with working out and/or putting sillicon implants inside herself? When her 2nd skin grew it convinently skipped her cleavage so she can look more sexy? She likes doing makeup in her spare time too? So many questions but no answers in her lore.
Let's talk about her skins now, specifically K/DA ones. Splash arts here are straight up ridiculously sexualized - just the right angle for the viewer to see her big, sexy bum and long legs but what strikes me the most are her ENORMOUS melons. Do you realize how big they would have to be when one of them is so visible from such angle?
I know that sex sells Riot but just because you can make some quick and easy money on horny teenage boys doesn't mean it's right for you to do so. Things like these cheapen the experience - every time reasonable people see K/DA Kai'Sa during loading screen they laugh at how ridiculously bad her visual design is. The best fiction characters are the ones that are believable, not the ones that are the most sexy.
This is what Kai'Sa could have been if Riot was more focused on making a good game instead of providing a good fap material just so they can make a few extra bucks.