@daniellecyr I think many of us would like to be able to place additional lots in our favorite worlds, but from what I understand, the game engine doesn't permit it. I doubt that they'll make an update to add it, because of that.
However, the way I look at it is that each "world" (Willow Creek, Oasis Springs, Komorebi, etc.) are all part of the same "city* but are different parts of it, different neighborhoods if you will. (That's also why it doesn't disturb my "immersion" to see Sims from other "neighborhoods" when I go to Komorebi or another part.) I "expand" my creativity by putting my houses on the empty lots that are part of each "neighborhood/world". (And putting Sims that I create in those houses to interact with my main Sim household.)
