A large part of SE's problem is likely optimization. I've been quoted second hand that Yoshi admitted the housing wards are awful sinks on server resources. So why do they keep adding them?

How often does the average player wander around these immense zones with just 30 houses. For me and mine, our housing ward is a ghost town, with only a handful of crafters camping the bell and board for the peace and quiet it brings.

My suggestion? Cut down the housing wards. Keep what we have now, but no more. Kick out players who bought a single house for themselves, refund their money, and unbind any furniture they purchased so they can sell it back. Will this be easy to implement or make those players happy? No, but SE kind of backed themselves into a corner with this one.

I can't speak for how their coders wrote up housing, but I'll tackle how I'd do it here: http://pastebin.com/DsEsZGfs

It'll take some rework of the code, but honestly it sounds like something needs to be done here.