It's the same thing with any other game. The publishers want the game out the door to make some cash for them as fast a s possible, while the devs want to make a nice game to be remembered.
However:
OE signed a contract from LA or Activision and thereby stated they could make Kotor2 in that time period. OE was even given a few months more to polish the game prior to release.
And I must say they did a great job - But no matter how big a fanboy you are, you can't just ignore the flaws the game has. I truly hope OE/LA, and any other companies involved, have learned that you can't rush a game like Kotor - Ever!