All you need to do is nerf Sett's damage
I guess I'm ok with all of his bullshit, but I just got out of a game where he did like 1700 in under 1 second with like Triforce, Titanic, and Deadmans. Having all of the shit he has, he REALLY doesn't need to have an Auto-target ult that also does Assassin-type damage.
Sett isn't fucking Zed, and he shouldn't be.