I don't think they will put that many lots down in one world. Look at the vampire hood. It should've had several more houses. City Living only had a few places to live. Many of the others around 20 and that included businesses ect.
Some places would be nice, but to add that many would take away gameplay and stuff missing from the game. WA was probably one of my top 3 favorites in Sims3. I think some would be nice when they can put in really nice gameplay like with Snowy Escape. Perhaps the Venice canals again like Sims3. A world with more tombs. Australia because of the kangaroo and adventure. Kenyan or African place to see zoo type animals. Rain forest adventure.