Subs & airships need to be completely removed from housing. Make a workshop instance in Mor Dhona or something easily accessible in the base game, and let existing workshops be transferred to the new one.

And now for the real hot take, that workshop instance should be available for all players, not just FCs. As it is now, there are plenty of people who have worked loopholes to own multiple FC properties and have become sub/slum lords. Those things print money (hello RMT source!). Offer it up to everyone. If SE is concerned about an influx of gil amongst players causing inflation, perhaps they should really look into the busted system of subs. :P

And for the scorching hot take, people who already own multiple FC homes on 1 account should be forced to give them up and have only one. Is your FC dying and leadership passed to your alt, but you're already owner of another FC & house? That's a shame, house is going to demo.