i apologize not my intent to make light of your home or desire to see some representation of it within the final fantasy sphere. i did go back an edited my post however to include that there were other living entities in meracydia besides just the dragons but it is know to us that Bahamut and Tiamat were very important to that region an birthed life there an that it was pilgrims seeking asylum who approached the elder wyrm "Dawn Father" Bahamut of the first brood to gain his trust an his protection and is the reason the Allagans were deterred for a time until they revived Omega which lead to the chaos that was all planned by the Ascians from the beginning an did lead to a calamity and rejoining of a shard when the conflict reached its peak.
if there is still a civilization left in Meracydia then its likely not having a good time with the hostile environment an likely under constant threat of the remnants of Allag i.e. war machines and soulless clones. though with Tiamat making her return there maybe that will somehow better things in some way but even if the triad returns it wont matter cause we have cured tempering an even found a repellent towards it.
i think Meracydia would work best as a standalone main quest similar to how the void was rather than whole years long continuous story as myself i saw others point out it would just be another heavensward tale at the end of the day an that would be even worse than the reception of Dawntrail with the new world in my opinion.