I agree with everyone that Coruscant should be in.
Dantooine is a little old, but is in great contrast with Korriban, so those two need to be in
.
Manaan had the most refined (and the most beautiful) landscape.
Also, the unknown planet was very attractive to me. Maybe there is some information about Revan stored in that temple (but that's storyline, I'm doing the planets here now) or the builders could help you out (I want to learn everything from them, I also spent hours listening to the sand people)
One planet of the Outer Rim should be a part of the sequel, I don't care which one.
Also, I'm thrilled about what has become of Kashyyyk (maybe Zaalbaar took leadership there when Revan set sail to unknown worlds)
Also, the environments on the planets should be larger, with more than just a cantina, a swoop race track and some appartements or a Czerka thing. A hidden forest, as a bit on Kashyyyk was cool.
My list of planets would be:
- Kashyyyk
- Manaan
- an Outer Rim world (where you could find Revan)
- Coruscant
- Dantooine
- Korriban