You know what Hexakill taught me?
Karma is amazing. I've been doing incredibly well with her. Karma is one of those champs you rarely ever see, is hardly played and is otherwise almost ignored. Yet.. She is quite amazing. Her kit excels in the chaos of Hexakill.
Every game I'll make play after play either saving teammates, or getting those kills that shouldn't of happened. again and again. Of course you still sometimes get those teams that no matter what they are just star crossed determined to do everything they can to lose the game, but even then I'll still be making plays and saving them. (Doesn't mean I'll win but, still).
Her ult and Q just scares most teams, even tanky teams with a good magic pen. The initial burst then explosion after renders their hp bars invisible quite quickly in those packed team fights. Her Ult and E can and will change most team fights, turning a losing fight into a winning one very quickly with the speed boost to continue the engage, especially if you have a sivir along with you as well. It also is amazing against many of the champs being spammed, such as Fiora, and Master Yi, or other AOE champs making their AOE's null and void at that critical moment.
The kiting you can do with her low CD slow on her Q which also can AOE in those tight confines coupled with her bind trolls even Ekko. I've already made 2 Ekko's rage because I've kept denying him kills with my Q and W combo making his target JUST out of reach. The shield on her E the cherry on top just incase.
She's one of those unsung champions that has an answer for nearly everything if you play her with half a wit, and are able to think during fights. (surprising how many people can't but that's neither here nor there).