Sett W having such high base damage even without grit is incredibly frustrating.

I have no issue with Sett's W gaining damage from his grit mechanic, since it provides a semblance of counterplay against his kit that isn't "play ranged or die"

The issue is from rank 1 through 5, it deals not just true damage with its base, but has the highest single-hit base damage of any non-ultimate in the game ( next patch will have it tied, at 90 base magic damage for her Q). I could be wrong on this so don't jump down my throat if I am, but I believe the next highest base damage is either 80 or maybe a scant few at 85.

This is damage which can not be lowered, unlike playing around his grit damage by going for shorter trades, and, in a melee matchup, is damage which can't be avoided if he just uses the ability as a followup to his E pull+slow/stun.

It's just an obscene amount of damage, especially for the early game, where health pools even on tanks don't reach much past 700. Like okay you know how % health true damage is so bullshit? Imagine if they did 16% max health true damage level 1 (90/550), which becomes then unavoidable at level 2, 18% at level 4, and 20% at level 5. That is the base damage on his W max before his opponent has a chance to buy extra health and without any grit.

I'm fine with the counterplay to the grit mechanic, I really am, but it kind of defeats the point of needing to play around it when he's firing off true-damage Aurelion ults every 12 seconds without having to utilize his grit mechanic at all.

I guess the counterplay to the non-grit side of his W is "sit under tier 2 tower and wait for Sett to go oneshot your midlaner so you can farm without taking a quarter of your health in true damage"