Honestly? There is a single thing that is entirely absence in DT in all aspects.

Substance/Depth.

Be it the story, the stakes or the characters.
If anything it was stripped from the characters we know already.

Everything feels 2-dimensional, it has no depth to it. The story feels paperthin, the characters are merely cutouts and painfully 2D.
They used to have different viewpoints on things, that was stripped in DT. Heck even Thancred and Urianger lack that. They basically support Koana just cause he asked and have no qualms in him throwing it all away for an objectively worse candidate.

Everything just falls into place as if the story tries to rush itself without any friction to the finish line.
It is such an on-rails experience that does not dare to introduce anything that would cause interest thast may detract from the writers goal.

It's especially felt in the last zone where we know these memories act like real people and such but are hammered over the head with "gotta delete this all, lol". No conflict arises, neither by the Scions, the Memory-people nor the WoL and it SHOULD.
As it was said so many times before:

- We as WoL are knowledgeable in civilizations, magic and Magiteck that would most likely be able to solve the situation and make Sphenes plan obsolete
- We as WoL and the Scions should have doubts and hesitations acting like the Ascians all of a sudden
- We have a long track record of preservation but this time we chose annihilation for a vague reason

It truly does not feel like an expansion but a hamfisted story using existing elements and discarding anything else cause someone wanted to tell their story in FFXIV and not a story about FFXIV, the Scions and WoL.