Nice work. I think I would've enjoyed an expansion like this far more, especially as it deals with the matter of Garlemald's future, and as you probably know from other threads, I tend to share your views on the matter of what I'd prefer its successor regime to be and the approach to its provinces, with some staying, others leaving, and so on. I also liked the way Corvos becomes their version of a Costa del Sol, and the comparison to Insomnia for the Inner Capitol. This has far less pointless fluff and is more focused on the story elements I'd be interested in seeing.
I also enjoyed how you handled the Elpis parts, and shifted around the role Venat played by swapping this and through involving more of the ancients who were more or less relegated to side characters by EW, if that. Historia Crux also sounds like it'd be a fun time and I like your resolution for explaining the three unsundered far better. The Lunar Subterrain, with Zodiark projecting images of their forlorn civilisation is exactly what I'd hoped for in the past. I am also glad you included the souls inside Zodiark rebelling against Zenos as this is something I had wanted to see out of the Zodiark fight we actually got.
If there is one thing I'd like to have seen it would be Venat involving herself with some being like Lavos or Jenova (or in XIV terms, related to the High Seraph) - something eager to devour or end their star, capable of approaching her, whispering to her and perhaps acting as the catalyst for her behavioural changes and inducing her ideological predisposition. Maybe something like IV: The After Years's Creator, which instilled in her notions as to how things in the world must evolve in order to avoid the fates of other worlds, so working a bit with the theme of the Dead Ends but without trying to cast it as inevitable. You could tie into this the Echo powers of a seeress, where she has visions of possible futures, which this entity is capable of tapping into and manipulating, and layer on acting as the primal's heart as further warping her and committing her to her path, which is where I thought they were headed with the whole 'heart' thing. This sort of entity I mentioned could then set up a future antagonist/storyline, later on exploring the cosmic destruction it unleashed on multiple worlds but on a slower, more organic scale, and later in the story arc.
I'd echo Skyborne's point on the sundered Ascians, and I'd also liked to have seen both divinities preserved in some fashion in the being into which Meteion will form, and not just Hydaelyn, as a being incorporating both light and darkness, which could perhaps have been a lesson drawn from these thousands of years of experience and modified into the concept with the sanction and blessing of what remained of the Convocation and those ancients liberated from Zodiark.
All in all, well done.
Yes, I agree heartily on this front and on the logic you provided for not doing that.