Everything UX-related in KH3 isn't treated with a 'you must get what's going on or else you're a pleb for not playing UX', but more so of a 'huh, why is this happening?' down to the journal listing Ephemer as ???, or even the Mysterious Girl X.
I mean, the reality is that the Secret Report has spoiled to us the ending of KHUX and KHUX proper hasn't even reached that point yet. ( the part where Luxu hands down No Name to one of them, or where the New Union Leaders transport themselves to the Sora World Line )
Even when it's a spoiler, for me, those were the kind that kindle interest and want to know how those things happen. I think that UX story is getting very interesting. However, the story is doomed just like BBS, because is set in the past. If they don't do something about Terra, Aqua and Ventus (which I hope they will, since Ventus is very involved in UX), you learned the story, they needed to be rescued and after they got rescued that was it. The same could happen to UX, once they get to the present (where Sora is in Shibuya), UX is dead.
I really hope is not, and I think Nomura is very involved in the story now, since he said he is the one writing the story and dialog all by himself. Everything implies that UX story is actually the future of the series, and I wish Nomura does more with it, because it seems like with the dark seeker saga he wrote himself into a corner after Chi/Unchained/UnionX were released.