Good question, and answers. I look forward to more suggestions. I always make the large lots communal places, reserving the small lots for residentials.
I have yet to decide what to do with that lot in the mountain though, as I do not want repetition to the rest of my world, and also to utilize the snowy mountain aspect.
One idea is to make a monastery, with a large temple and court yard. Give it lot assignment residential, and create a large household of unrelated sims to be the monks. Make one famous, to attract the masses, have the lot trait Celebrity Lot. Place some items down to simulate religious life, and have large parties inviting only the criminal sims in the world. I think I see a path for the young Ito girl..