I think 13 worlds is a bit much, and Endor, Dagobah, and Hoth are uninhabited, unless you count Ewoks. Keeping with the current model, I'd cut it down to
New Sith/Jedi academy - Beginning
Corellia- The Corellian system has 5 habitable worlds, so this could be a major part of the game
Iridonia
Dantooine(I like seeing how it develops, and I want to see that statue I had commissioned of myself) Throw in some houses and such, it needs to look more like a population center.
Onderon/Dxun (I want to see more than just that one little tiny part of the city, its the only city on the planet so its gotta be pretty damn big. I also want to see the Mandalorian base several years later after getting those other clans to join in Kotor2)
A True Sith World (Make One up its EU) - End boss stuff