Kotor 2 was a decent game (aslong as you don't factor Kotor 1 into the equation) until Malachor V, at which point the entire thing erodes into a festering ooze, from which nothing good can be salvaged.
Never played Neverwinter Nights 2, though, and Alpha Protocol was just painful... I was disgusted with myself for wasting around $20.00 on it (after trading it back into Gamestop... 2 days after purchase)