I think it's a cool idea - and would go even further - the whole behaviour of NPCs (and PCs) should be more connected to their alignment and their goals in life. e.g. - greedy mercenary's ( ) behaviour depends on how much money you pay or if he/she resists the fear, he would take more loot ... good charakters with a goal to fight evil can get some resistance-bonus when fighting evil, "normal" saving throws to fight neutral charakters and malus when fighting good ... and so on ...