This may be sound odd, but well. Here we goes.
How about a dual Nature? Dark and Light. If one goes up, the other goes down. With a limit of 0/7, when Light is four, Dark is three, for example, and vice versa.
A jedi can choose which Nature he want to test. Of course, if he test Light against her aspects, then he is risking to loose a bit. (Or maybe a lot.) But, if he prefer to test his dark side, he is gaining a test for advancement for that Nature.
The Light Side aspects can be: patience, peace, meditation, harmony.
The Dark Side can be: fear, angry, hate, cause suffering.
I prefer that way too. I like samurai. 
And, what about spaceships? Perhaps should be treated as characters, with their own stats, or as gear, with bonuses and penalties?