Ok now show us their server structure, if these have an impact on gameplay outside of housing, if they are client-side or server-side and how susceptible they are to hacking.
You may not know, but most MMOs have housing as a pure vanity thing which works client-side and does not affect gameplay at all (so they don't care about hacking), while others have a very limited presets with no place for personalization, in any case these system can't be applied to ffxiv w/o turning housing into a cheesy vanity system with nothing more than boring presets.
Even if housing affects us all, this is a topic that requires a minimum level of knowledge... don't take this as an offense, i'm not an expert but you seem to know very little about how this kind of systems are managed.
Wards don't take server memory, this would do nothing, separate wards for personal hosing would work.