Personally I would love to see any or all of the following planets in SWTOR.
Kashyyyk (along with a playable Wookie or companion wookie *Not just Smuggler* species)
Dantooine
Manaan (With a Selkath companion)
and/or Mustafar
Would be nice to see an Expansion pack eventually with several planets, some new ships, new playable races, and additional game content for 50+. I'm sure I'm not the only one to want such.