Ability to set house/roommates personal space & items.

I think locking doors is a good option if you just want private bedrooms and bathrooms, or even private apartments though it might be difficult to see what everyone is doing in different places. I've never had issues with assigning computers either. Also, from what I've seen, sims tend to use whatever furniture when you first start playing them, but once you get them into a routine, they sort of learn which furniture they need to use.