Titan Buttons said:
What exactly was missing from the game
A few planets, multiple story arcs, about 10-15 more hours probably. Remember, there was a whole bunch of setups for quests that didn't go anywhere. HK Commented several times in KOTOR 2 about who awful it was that there would be copies of him, but never being resolved. It's also why the ending involved just a clip of the Ebon Hawk flying away.
Lucas Arts was acting like it's typical dumbass self and made obsidian kick the game out the door after only a year without it being done. All the incomplete data was on the disk, but the game was made so it couldn't access it.