Oh, I would looove to have an alien world where the sims could live in.
Sixam is beautiful, but it is not a normal residential world. I tried to change Strangerville into an alien desert planet, but it is not the same. And although it looks like a sci-fi world, I don't like playing in an 'infected' Strangerville.
I still wish for an alien update:
Sixam: bigger and as a residential world, after the first sim discovers it
Aliens: CAS update and more abilities
Buy&Build: alien technology