We've gone over this topic many a time and will do so again as long as there are new players to the game!
The game designers were extremely foolish to assign such high EX to the good NPCs and NOT enforce the oath players take early in the game. I keep hoping that was their original intention but somehow got left out or overlooked when they had to rush the project to get it to market.
I, for one, do not like killing the good NPCs. I like them. Gael Serran is better for their being there! I like to play the game in such a way that Gael Serran is better for MY being there too!
Wyv