Pretty much this. Wuk Lamat being a Mary Sue is a symptom of bad writing, not a cause. She had nothing to do with:
- the hanuhanu not knowing their own cultural rites despite practicing it yearly
- the pelupelu rite happening offscreen while we just chill out camping
- moblins not knowing basic commodities and hygiene
- Thancred and Urianger appearing as rivals and then...nothing. Back to being allies over and over
- letting Wuk Lamat go back to town alone, surely nothing bad could happen
- Valigarmanda being a glorified hunt target (narratively, not the fight itself)
- Gulool ja ja neglecting Mamook for 80 years despite being a blessed sibling himself
- Bakool ja ja commiting several acts ranging from cheating to what would be considered a war crime with zero accountability
- cooking competition as if nothing happened (does Gulool even know what Bakool did???)
- cooking competition basically contradicting what was previously established with how the rite of succession works
- Bakool ja ja (again) having an unearned rushed redemption after we learn his tragic backstoryTM
- Zoraal ja's daddy issues and extreme golden child syndrome thrown in last second to make him less a plot device and more a character for more tragic backstoryTM brownie points
- Zoraal ja being a "we have Zenos at home"
- Ketamine pulling an Y'shtola fakeout death on us
- the WoL and Erenville forgetting what linkpearls are as they watch an alien spaceship very slowly fly toward Tuliyolall
- Zoraal ja spending 30 years in Alexandria honing his skills, yet he still lost to his old, literally half dead dad
- the whole gang watching Zoraal ja's evil monologue as he unalives his dad and walk away scotch free (bonus points: ALISAIE of all people stops us from going after him)
- playing Smile as we build a bomb. (but we're building it with the power of friendship so it counts...I guess?)
- the army Zoraal ja spent 30 years building decimated by cowboys with rubber bullets and Dragon ex machina (this one was cool tho)
- that f***ing baby
- Krile getting 5% screentime, when the whole B plot is indirectly about her
- that f***ing baby stealing what little spotlight Krile had
- the Scions basically just existing as trust companions, pretend they're not even there
- the entirety of Living Memory
There's probably more but that's what I came up with off the top of my head. Now add every moment Wuk Lamat is involved on top of it and we can see why most people are unhappy with the MSQ. Heck, I like Wuk, and at first I genuinely thought "ohh it's just me being nitpicky, let's see how it goes" but the more I played, the more I questioned things, and at some point I acknowledged it wasn't me, it was the writing.