Another possibility was that Obsidian was told to avoid tampering with the events of the first game by LucasFilm as much as possible. It wouldn't be the first time that's happened with expanded universe stuff.
With SWTOR, it would've been the opposite because SWTOR was seen as a good money making opportunity and the events of KotOR I and II would've been all up for grabs to use however they wanted to make that money.
People underestimate how complicated making a video game, especially one that involves licensing rights, actually is
