to avoid town builded by a single person, could be enough give differents chanche on he building.
Example - Magazine Building.
1 - Hole in ground for few peoples, it keep meat and seeds safe and fresh.
2 - Leather tent with big hole underground. For more free space, not so hard to build.
3 - Little Wood Magazine, "Not so little" to be build by a single person if he don't need. Ok, maibe someone will build it anyway, but not the whole hh.
4 - Stone Magazine With Underground Hole Inside. C'mon, you need to be really a town to need it, and to build it. :3
(Maibe i have give too many builds for the same type..her..well, it was just and example.)