It's for more likely the destroyed cityscape dungeon is just another themed dungeon, than anything actually indicative of where the story goes.
That's true, but that one Persona 4 dungeon is indicative of where the story goes. I'm just saying that the possibility that the apparent dungeon with the destroyed cityscape in #FE could be as well is there. Hell, the fact that the dungeons themselves are "fake" (e.g. the clouds in the picture you posted are held by strings on the ceiling) could be indicative of a lot as well, which is what we don't know about the game right now.