What about a good and evil sistem to help with the RP in the players. Based on what you kill (evil creatures, good creatures, neutral creatures) you could have 2 bars that would fill up really slowly in order to make your alignment good

or evil

, or just keep it neutral

What would be the benifits of this (Besides players going "Muhahahaha, I'm soo evil"):
1- NPCs could react diferently acording to your alignment, dont forget that fear is a form of persuasion and certain NPCs may give certain quest to evil players, although religious and order loving NPCs would not give quests or repond rudely to evil players, but they would treat the good and kind players nicely.
2-There could also be certain perks, such as magic boosts, like Red and Dark Way for evil players, and the same, only with diferent Ways of magic,for good players.
3- Roleplaying could also improve as players could start demonstrating more amrking in-game personalities as they are kind adn good or rotten and evil.
4- There could aslo be some special skills or magics for players well aligned with "Good" or "Evil", not to mention special quests.
Just another ideia

"Hope it's better than my last ones"