It's pretty obvious the housing system in this game isn't scalable for the size of the modern player base and adding more wards in the current system probably isn't a wise idea. Every ward you add is just another area that'll remain empty unless there's an RP event/location there. I've walked around pretty much every ward on Lich, the home world on Light DC, and they're dead with very few plots even looking noticeably different.
With that in mind, why not have instanced housing? I appreciate the RP and social elements for the few wards/plots that have these within them but beyond that, they're a ghost town. Not to mention Island Sanctuary is coming which I'm going to assume will just be a housing plot you can eventually upgrade to large contained within its own bubble.
Now, I don't want "lazy" instanced housing in which all existing plots are combined into one giant ward that you then enter each plot individually. There's room to make it much immersive while sacrificing the ability to walk through 24 unique wards per district per server.
Right now the five districts are all contained within big cities but there's room to put smaller housing locations in the towns and settlements around the entire FFXIV map. You could even place more apartment buildings with this also (and an extra addition would be larger penthouse-sized apartments).
Why just live in The Mists or The Goblet (lol) when you can have an apartment in Costa del Sol or a small house in the Azim Steppe? Each town could have an apartment building at least along side an assortment of small/medium plots. There would be room for larger housing areas in the big cities such as Old Sharlayan alongside this to still have the traditional areas.
Design wide, instanced housing would allow for more realistic placement of the housing plots and apartment buildings into the normal game world. Again, I do appreciate the lost "immersion" his would entail but seeing as most wards are empty on Lich, I'd rather have housing buildings/plots be in the main game world with generic appearances on the outside.