How has Sett not been nerfed yet?

Sett is a champion with ok design, however, he is able to tank way more damage than he should be able to and dishes out a LOT of damage for that tanking.

Sett's W is ridiculous. Grit loss should start way faster after taking damage and the shield he gains from it is just not ok. Sett can fill almost his entire health bar with a shield and 1v4.

Sett's E, when he doesn't get the stun from 2 champions, still "stuns" the enemy for way too long. The knockup effect that results from it just disables the enemy chamion.

Sett is a champion who can kill everyone without even dying and can just go under a turret with half the team there, get a triple kill, and easily get out.

Not to mention the fact that all of this is amplified due to the fact he can get fed very easily since he has not only a super strong late game, but a pretty strong early game. This is another Aphelios situation where he's just too strong.

These champions are getting pumped out way too fast for thorough testing and just make the game unfun. Exhibit A: The bug where Sett's ultimate would permanently stick the target to the caster (Sett, Sylas)