I'm hoping that in the future they will open up all the dungeons as new open zones. But with more areas open/unlocked than we had during missions. Sastasha and toto-ark have places named on the map that just don't exist in game, locked behind doors and vines. I really have no idea how stone vigil story and hard maps intersect or combine, I would love to see the fortress rebuilt somewhat and/or quests to help rebuild it. Would love to see a minecart ride wind from norther thanalan to deep in coperbell, rebuilt into a semi functioning mine again.

How nice would it be to explore dzemal darkhold and see how the areas fit together, instead of getting teleported around. There are paths covered here too that I'm curios about. Same for Halatli, some parts are pretty copy/paste in hard mode but that place could just be a labrenth of "training" fun

And best of all, if they could unlock these areas they could create new open world areas to make materia. Also they could make more instanced outside areas. Right now it's restricted to guildhests and special story quests.... But why not an outside dungeon? Beast tribe areas could setup different areas for bosses. Why not have a poacher invasion in the shroud? Garleans invade whatever area their in for supplies and we have to stop the impending attack? Lots of possibilities to add flavor and content to the world without having to design all new areas.