Korriban is famous for its affiliation with the dark side of the force. The sith race made their home here once and has come back to join the war. The sith have created a Sith Temple in imitation of the Jedi. The sith have pulled force sensitives and warriors from the unknown regions and outer rim in preparations. The Sith are coming back stronger than ever and Korriban is only the start
The home of the Mandalorians, Mandalore is where the Mandalore sits as he commands his troops to conquer and destroy. The Mandalorian base is here so it would make sense that Mandalore must fall if the Mandalorians are to be stopped.
Geonosis, is home to a bug species called Geonosians. Right now Geonosians mind their business, but will be conquered in no time. Those Geonosians should best prep their sonic blasters!
This Endor is actually the forest moon of the gas planet Endor. It will be referred to as just "Endor." Endor is home to Ewoks, a small bear-like species. Ewoks did defend themselves with the help of the Rebels, But this time the Ewoks have no help, they are alone up against Mandalorians, Pirates, Sith, and who knows what else. The poor little creatures might be doomed.