I cant think of a single thing I liked about the dawntrail MSQ.
It ended.
No, wait, that was still polluted by that godawful song, never mind.
Anyway I think comparisons to Stormblood are not wholly unwarranted, but even at its worst points SB wasn't as bad as basically the whole of Dawntrail, and its high points are significantly better than anything Dawntrail manages to muster.
Stormblood's worldbuilding expands on stuff that had been semi-established before, like Ala Mhigo and the Far East, with a narrative that is at least somewhat coherent (even if it is a bit unfocused) and generally keeps its lore in line with the established setting. More to the point, the places you go feel real, they feel lived in, they are built up enough and populated by characters who feel like they exist in a real world.
Dawntrail is a trip through Mexican-themed Disneyland (Tacos! Tequila! The only thing missing is some sombreros and a mariachi band) where the world feels profoundly empty and unreal. It's a theme park, where all the scenery is just empty facades, and the characters are ethnically themed mascots. To boot, it wholly ignores one of the few bits of lore that was established about the New World, with absolutely zero sign they are going to acknowledge the existence of the Whalaqee whatsoever. (Admittedly I suspect this is mostly down to SE's boneheaded policy to never acknowledge side content in the MSQ, which has resulted in the Whalaqee being banished to the abyss because it's Blue Mage stuff.)
I would also complain about how Wuk Lamat, princess of this whole country, somehow knows basically as little as the WoL does about the country she lives in and is set to become heir of, but nah. There isn't enough substance to any part of the New World for her to know about anyway.
Then after meandering about with something completely pointless that ultimately proves not to matter at all for six levels, it pivots into retreading a worse written version of narratives that ShB and EW already explored, handles it even worse, and ends on a dollar store redo of the Endsinger fight except Wuk Lamat shoves you aside to take center stage as the true main character of the expansion.
It's a total mess.
But TBH I think it's not unsalvageable going forward, even if all future players will have to play through DT. Personally I got through it the first time with judicious abuse of the Esc button, after checking out of the story by level 91, so. I only played through it "properly" when I was levelling an alt for raid stuff later, and resolved to give it a chance. Big mistake.
I think the point where it would become truly unsalvageable is if 8.0 drops another DT-tier bag of flaming dogshit excuse for an MSQ on the playerbase's collective porch. They desperately need to follow up this Stormblood with a Shadowbringers, in terms of MSQ reception, if they're going to salvage this game's reputation for "excellent story".