Wards consume far too many server resources in exchange for too few houses to be a sustainable long-term option. Adding more wards is a bandaid on a broken leg.
If it is feasible with FFXIV's current infrastructure/server resources, I strongly urge Square Enix to provide players with an instanced housing option, not as a replacement, but as a second alternative to Housing Wards.
Players who badly want neighbors can try their luck with wards. Players who don't can have an instanced home. Two ways this can be implemented are:
Option 1) A gate in each city that when interacted with, leads the player their own personal instanced S/M/L housing plot with a lawn.
Option 2) Allow apartments to be upgraded to the size of a S/M/L house. This sacrifices lawns, but makes apartments a viable alternative to houses.
With both options, players could keep upgrading the size of the instanced plot or apartment with more gil.