How you define the Force will largely define how your interpretation of Star Wars plays.
I would like Jedi to not be superheroes, and I would always like the Dark Side to be a temptation, but one that can be atoned for.
Some really broad ideas:
- No Power Points. Instead, as in Lankhmar or Solomon Kane, there is a base penalty that you can buy down with concentration. The Dark Side being faster means less skilled Sith will be more 'powerful' than their pure hearted brethren, but at a cost.
- Governing skill is “The Force” (Spirit). This is what you roll against.
- There is a ‘Light Side’/’Dark Side’ (Spirit) skill that is akin to Guts, but may go up or down depending on actions and/or failed Fear checks and the like.
- Light side users may choose… at any time to use Dark side techniques. Each time this happens you reduce your Lightside die by one step. When you go down from a d4, you have Fallen. This reduction can only happen once per scene, so Anakin did not lose a step for every one of the sand people that he butchered… Just one.
- Dark side users suffer half the penalties of Light side users when invoking Force powers.
- Dark side users suffer mutating effects on critical failures as the Dark Side greedily gnaws away at them.
- Light side users suffer a point of fatigue on critical failures.
- Dark side users suffer a wound every day that they do NOT invoke the dark side appropriately. You either use it to consume the world around you, or it will consume you.
- Want to be redeemed? Play it out as a dramatic task, while taking a wound every round... Or something...
- Light side users powers will typically be defensive, or enhancing/controlling oneself.
- Dark side users powers will be focused on external manipulation and domination of others. Self control and self awareness are not hallmarks of the Sith.
- Lightsaber Combat would be ONE edge. This edge would set your 'to hit' number with ranged weapons from the standard 4 to whatever your parry is. There would also be a combat option to simply deflect blaster fire. No need for multiple edges to reflect styles as there are plenty of existent edges to tailor melee combat technique.
- Speaking of lightsabers, if you don't have the Force Arcane Background, and you critically fail a roll, you roll on the critical injuries chart and that is the part of your body that you no longer have...
- Does your Jedi have the Berserk edge? Did she just kill a minor informant with her lightsaber to prove a point? The Jedi Code and conduct will need to have some mechanical backing. Perhaps it is simply a 'savings throw' type of mechanic with a penalty based on the action taken. If you fail, drop your Lightside die a step. Willful evil actions would of course allow no 'save'.
- The Light/Dark side 'skill' mechanic does provide a 'sink' of sorts for players to spend advances redeeming/damning their characters.