I'd definitely like to see more types of buildings and stores. I have made a couple but it's not the same as having a proper in game one and doesn't work properly either.
It would be fun to be able to build our own working police stations and hospitals as there is not much point in getting the reward stuff in those careers unless you can use them.
It would be good to be able to build big apartment blocks like in San Mochino (not sure how you spell it but you know where I mean) but in the other worlds.
I agree with Movotti, definitely less rabbit holes and I'd like to see more careers we can interact with and play rather than the sims just go out to work and come back.