Kai'Sa is already broken, ... but I was thinking about how allies can apply stacks of plasma for her through immobilization effects.
Aatrox has the ability to apply immobilization more than anyone that I can think of.
Kai'Sa still needs to apply the last hit to detonate them, but would this not be even more broken??
I haven't tried this out myself, so I am not even 100% sure that it works, but the logic seems to work.
Alzon1 votesAatrox also has to hit his sweet spots...
Alistar is more likely to get three immobilizes off in a single rotation than Aatrox is.
Elite4Runner1 votesI didn't say it would be the easiest,.. but if you had someone who was mechanically skilled with Aatrox it would be better than Alistar. Plus you have to keep in mind that all 3 of Aatrox's sweet spots are AOE. The first is really only large enough for a single champion, but theoretically he could hit both laners with 2 and 3. Also, his W is an immobilization as well.
Tr4shB4NSYST3M1 votesIn theory it could work however, A- Most adc's outrange Aatrox Q sweet spots and B- Aatrox really needs levels (base stats) and Items to not be super squishy. I think that the aatrox would have a really hard time, especially against a double ranged lane, 
would absolutely crush 
Elite4Runner1 votesEverything is going to have a counter pick