No, it doesn't get any more difficult. In fact, it gets even easier. I just finished the game as a Sentinel/Jedi Master, hardly a combo that should make you an unstoppable force with a lightsaber. Yet, at the end of the game, I simply cast Force Enlightenment before each battle and then sliced through even the most difficult enemies like a hot knife through butter. Remember how fighting Dark Jedi in KOTOR I meant that you had to deal with their force powers? Not so in KOTOR II. They are basically just regular melee opponents with lightsabers.