Having sat on it for a few weeks, I think I may have liked the 6.x series more if I'd gone through it all in one go instead of being drip-fed the story over a period of two years.
While the conclusion was well executed and the story itself was decently written (aside from the occasional cumbersome dialogue), it just felt like a lot of waiting around to be ferried to the next plot important event and the foregone conclusion of our victory was even more pronounced than usual which made the stakes feel completely nonexistent. Endwalker and Shadowbringers both let your all-consuming hero crown slip a little bit at least once each, whereas the one time in Newfound Adventure where you take a loss there's not even a shadow of a doubt that we're just going to rush back in and destroy Zeromus on our own terms.
Echoing what a few others have said, the alarming lack of any internal conflict among our allies is moving very swiftly into completely implausible territory. With all the narrative ground to cover in Endwalker I was willing to excuse it, but the mere prospect of significantly contributing to Garlemald's restoration should at the very least be remarked upon by anybody considering the amount of division the empire left behind and the fact that had they not fallen to internal conflict they would have gleefully continued their offensive in Eorzea without a second thought. Even if the outcome remains the same, I think it would benefit the story a lot to present some differing viewpoints or any kind of discussion.
More than anything else, though, I'm at least glad Y'shtola finally got some solid hours in the limelight. There's nothing wrong with a static character, especially with this cast, but it felt nice to finally get a glimpse into her motivations and character beyond sardonic one liners and being assured by that narrative that she is indeed moderately intelligent.
Knowing what we do now about Dawntrail, I feel like it would have been a better move to leave 6.1 as is, and branch off into the voidsent friendship adventure from after Alzadaal's Legacy much like they did with Myths and previously with Sorrow of Werlyt, and then spent the rest of the patches on the trail of Galuf Baldesion throughout Sharlayan, Garlemald, and Thavnair, until we ultimately find the old letter and prepare to go to Tural. A more grounded adventure seems like what most people expected based on the way it was advertised, and it would have made much better use of the new zones that were in my opinion just a touch underutilized. Oh well, best is yet to come, hopefully.