I would like to see shared houses. Something with fixed outdoors, but instanced indoors for 10-20 players. Imagine how active could a whole ward of such houses be.
Neighborhoods are awesome when you live next to free companies that have dozen active members, as they tend to spend time near their house. Ghost towns are mainly caused by personal houses and shell FCs, because time is limited and what would be the point of visiting a place where nobody is waiting for you? Large downside of residential areas that there isn't much to do when the zone is empty. Events or something like Gold Saucer activities would help to improve that.