I feel that we'll at the very least get a variant dungeon for the 3 city-states of ARR. Considering the one for Ul'dah was Sil'dih, I'd guess we'll get post-Bahamut West Shroud for Gridania (here's hoping that's where we'll see the elementals) and The Floating City of Nym for Limsa Lominsa. I could be 100% wrong, but these would be solid options imo.

For anyone that doesn't know, West Shroud was an area in 1.0 and the only time we went back since ARR was for the Feast map Lichenweed. West Shroud is that area covered in yellow aether crystals you can see from North and South Shroud.