I can't remember where I read it, but I do recall someone on the dev team mentioning the other pieces of Dalamud that fell as being "something we would visit in the future".

When I saw the footage of Aethereochemical Research Facility and Fractal, I actually figured that was what those dungeons were, but I was pleasantly surprised. I assume we'll explore the dormant pieces later... and probably discover they're not quite as dormant as we thought.