I proposed commitment as a way to measure how closely you are following the tenents of your order/ tradition. If you want to play a Jedi but you act less like they should and more like a laser sword thug, then you don't get the benefit of being rewarded by reaching 100 commitment.
Yes, I would sooner see narrative drawbacks for it, such as the 'lightsaber thug' being distrusted and eventually outcast by the other Jedi. Just as a heavily cybered PC might have NPCs sneering that he's a 'wannabe droid'.
After all, players are gonna see that in the movies, that little use of Dark Side points eventually allowed Luke to defeat his father. Anger is an energy.
I personally feel that if a player wants to run a 'falls from grace' character like Anakin, that it should be role-played out of choice.
That said, maybe the plethora of Force Dice in F&D may need some mechanical rein on the characters,I don't know. How many will they be allowed to attain?