I think we should just divide the city into neighborhoods, but leave it open for people to do whatever sort of 'city' they want in there, just like the Guildworld was open for people to do what they want (Although I don't think anyone made a future setting except Waldronate and it was kind of a post apocalyptic fantasy setting). Also keep in mind that we might need it to be able to expand, so perhaps mapping out a core general layout to cover the initial participants, but keeping in mind we may need to tack more neighborhoods on if more people join in as does happen. Perhaps we could also have a list of important sites/buildings people also get along with their hood (could also be random pick). Such that someone might get a university, and someone might get a palace, and someone might get a town council building.