Mandalore. Flashpoint/Ops: Fight the Mandalore Crypt in search of the original helmet.
Mustifar: Similar to Illum, fight for rare crystals that grow from a special ore from x planet and form from using Mustifar Lava.
Kasshyrrrr******k: Wookie Civil War
Telos: Kotor 2 conclusion of what happened there.
Duxun and or Onderon: Conclusion of Kotor 2
Dantooine: Rebuild to Jedi Temple?
Ruins of Malachor 5: Trayus Acadamy: Off branch of Sith of the Empire have reconstructed the remains of the Trayus Acadamy as well as connecting parts of the remains of the planet that have not drifted.
Since in canon star wars games will end with the protagonist being light sided that pretty much makes Malachor 5 impossible, it exploded, there is nothing to see except debris floating in space.