Yea, I got that vibe too when reading about spoilers of the endgame stuff.
It feels at least in parts as if Nomura wanted to "get over with" the current saga as quick as possible and resolve the mess he himself somewhat created in one giant big bang with so much being crammed into the finale marathon that much feels not in-depth enough.
Mentally he's probably already completely entangled and invested in the ideas and concepts for the new saga to which UX serves as the groundwork with some elements from KH III thrown in.
Thing is though, the new saga has the potential to become an even greater mess if it is approached with the same mindset as the just resolved one and has on top also a bunch of new, more complex concepts thrown in.