Which leaves the question of "Why go back to Garlemald?" (other than, heavens forfend, being without the company of Alphinaud and Alisae for more than a patch).

... my guess is that, knowing the dimensional barrier in areas of Garlemald is already weak, we're going to cross over into the "ice" reflection for some reason, and the architecture of wherever it is we first find coincidentally bears similarities to Garlemald's concrete brutalism.

How that factors into the greater picture of 8.0 I still don't know yet other than introducing further dimensional crossings.