Why are people assuming the house isn't a instance already? Cause it is. The wards serve only for the purpose to access this instances easily and the wards isn't the problem, they can easily multiply the wards, cause they are an instance as well. They already told that the problem with houses is to store the amount of data generated by each single house.

And yes there is socializing in wards, is not cause you never saw it, that it doesn't exist.