I'll try to keep this as short as possible.

I think we can all agree that losing our house because we want to take a break from the game, or can't afford a sub due to financial reasons, simply sucks. The effort required to get a house in the first place (or rather, the luck involved) is already significant, not to mention the gil and time spent decorating it.

Our private island already has enough space to place a house of any size. That alone would solve most of the problem: everyone could have a house, whatever size they want.

But what if you want to live in a neighborhood? No problem. Once you've acquired a house, you could relocate it to a neighborhood plot if you prefer.

Instead of a demolition timer, we could simply have a relocation timer. After 45 days of inactivity, rather than your house disappearing into oblivion, it would automatically relocate back to your private island plot.

No house lost. No furnishings lost.

(Of course, this would only apply to private housing, not Free Company housing.)