The only way I could see them having resources to do it is if they release some distant future expansion in the same vein as FFXI's Wings of the Goddess pack, where the player revisits familiar areas but in a different point in time. If they focused that expansion back on the original ARR areas but in some alternate dimension, they could potentially use it as an excuse to rework existing maps (for the new dimension or time-travel variant) and get double the benefit from the effort invested. The calamity situation makes that a bit awkward, though not impossible depending on how they work around things.

For now though, most people want to travel to the completely new parts of the world map.