Maybe I'm coming at it from a different angle because we use light side= law (discipline, order, restraint) and dark-side = chaos (passion, emotion, 'anger is an energy'). So the rules we see in EoE (flip a destiny to use DS pips) are simple and work fine for us.
However, I still wanted to reflect the SW universe which was heavy on 'karma', and that bad stuff comes around to bite you in the end. Any group can play what they want, but it just doesn't feel like SW to me if the Pcs are 'murder hobos'. Han Solo and Boba Fett didn't just murder innocent people for fun. I like EoE being about shades of grey, but not casual murder.
To be honest, I don't think a game mechanic is what's needed here. Sounds like the GM should talk to the players about what's expected of the game and when they are going too far.
Edited by Maelora