I was thinking of ways to give the game a more open world feel. I thought "why not just build the whole neighborhood in one of the big lots?" With the ability to lock doors you can already build your sim a little apartment anywhere. I had a sim living on the second floor of a gym. I just made the apartment, locked the door for everyone but my sim and just never left. The townies all started getting really buff, lol.
I was thinking of doing something like that. Maybe a new venue, call it "neighborhood." Why a new venue? Open up interactions without messing with anything in the other venues. So on this new venue a townie can come onto the lot without being invited and interact with anything there like making food, cleaning, or even using a bed; not just napping on one. Also set it so that they stay indefinitely or at least a very long time. So you have some people "living" there. I think it'd be cool if you could stick a bar or cafe in as well. Be able to put down the bar or counter so that an NPC will come in and operate it. Maintenance person shows up to fix stuff without being called. Permanent maid on site maybe.
I have a basic understanding of how modding works but I really don't know how to approach doing the above or even if I've outlined the most efficient way of doing it. Anyway, just some thoughts.