As someone who's thoughts on the msq in terms of quality can be summed up as 'mixed bag', I have to say that there are a lot of parralels to Stormblood.
Two expacs worth of story crammed into one expac
Nominal main/original one is the less interesting of the two
Both main plots feature a female deuteragonist taking up a leadership position on what can charitably be called 'shaky grounds'.
I think this expac really just needed one thing; to be split in half. One expac covers the southern continent, another the north.
It's kinda wild, because it really feels like the southern continent's contents cover basically everything you need for an expac on their own. The most likely tribes - Moblin, Mamool Ja and Yok Huy - are all on the southern continent, and the 7 challenges would have faired a lot better if each had a whole zone for it, rather than some of them being "go to the city and come back with that guy who's really overstaying his welcome by this point". The plot even largely wraps up it's original goal by the end of the L95 quests, to the point that Shaaloani is basically just dicking around for a zone playing rootin' tootin' sheriff.
What's wild about this, to me, is that there's a pretty good way to split these all up already. THere's three perfect candidates for trials - Valigarmanda, Bakool Ja's spirit or whatever, and Zoraal Ja. I'm pretty sure you even have enough allies with you for Bakool Ja's spirit to be a trial, so I don't know why it was skipped. And it would have been so good to have some of the other candidates as dungeon bosses or something. The game really let me down on letting me actually have a fight with Thancred and Urianger.
Really, the whole expac did Koana dirty. LAd's supposedly equal with Wuk, but he gets so sidelined it's painful. I wanted at least one dungeon with Koana's team instead of Wuk's. At the very least, if they'd given him another scion as an ally (maybe split the twins) then he'd feel more fairly balanced with us. Could have given him Y'shtola with barely a second thought, she both makes snese as someone he'd want to grab, and someone who compliments and corrects his mindset. Or split the twins between the two.
Conversely, the second half also would have benefited from being it's own zone. Namikka literally only exists to die, it would have been more impactful if we did some questing with her as a real party member before finding her all Old in the dome. And similarly, that could have done with it's own arc too. Cahcuia was much better because she was basically with us for a whole zone as a mission control.
And that way, you have the whole southern continent to dedicate to expanding on the zones, and really giving them their own identity. And when it comes time to the northern content, you have more than a single zone to work with for your western theming or whatever you want to do.
With that said, contrary to most opinions here, I actually really enjoyed the last zone. I was so thrown off by it's discovery, and the whole thing just had this... really melancholy air to it. The one thing I will say I did not like, though, is that the volcano was absolutely torturous to traverse on foot, and they were way too stingy with letting you jump down.
