I feel like some of you forget one primordial thing : this is a collaboration, based on a non-FF game

As far as I'm aware of (correct me if i'm wrong), none of the collaboration were impactul on the FFXIV storyline/universe (not even FFXV or FFXIII collabs, which is a bit odd, but fair enough).
They were just "bonuses", things "added, out of this world". they were not meant to tie deeply into it.

The only difference this time would be the tremendous amount of content spent (I would have said wasted but this is my own opinion, it doesn't count here) on that collaboration (3 raids and I-know-not many quests).

In the end, this is just a non-FF collaboration.

I'm sorry, but reading you all made me kind of "happy" (well, a consolation lot would be more accurate) they didn't seem to try to tie Nier in FFXIV