This is not necessary, the problem with housing limitations comes from pure server space, to add more housing they have to buy more servers, something they will be doing in the future, because we are already paying for it, physical CEs and cash shop, if you want to support their income so they can add more housing, use the optional services.

And to inform people who seems to ignore the base of the problem, because of lack of knowledge or whatever, making housing instanced wouldn't solve the problem, the memory limitations are related to the big amount of data saved for every house, the neighborhood does not take sever space, so making housing instanced would only make it lees interesting.