Sorry for being a Lawbreaker and using thread necromancy, but:
I have been fiddling with this for a while and didn't quite get it right so far. May main problem is correctly incorporating the set of Control powers (like force speed, jump, etc.) and the Sense abilities in an Evocation kind of way.
Oh, and I would reflavor skill names as to not run into the who uses Conviction or not thing. It could just be the raw force power of an individual..maybe re-rename it to Resolve or some other thing that fits..
For the Dark Side I would go the Lawbreaker route, this is what I came up with so far:
The Dark Side
It’s always there, waiting, luring you in with its quick, but costly power. Each force using character must buy a power for [-1] Refresh called Temptation of the Dark Side. Whenever a character wants to call upon it, he must describe how he draws upon his dark emotions to enhance his force power, corrupting it in some way and netting him an immediate +1 bonus to his Force checks. When doing so, he must roll Discipline against the result of his Conviction/Resolve check, as if he were defending against an attack (this is basically the Demonic Co-Pilot). Failure to defend results in mental stress as if from an attack; psychological consequences that result are set by the GM, usually being some state of heavy emotions leading down a dark path. These can, of course, be compelled to have the character make use of the dark side again.
If he is ever taken out by mental stress in this way, he immediately gets a new power, which replaces the temptation and is called Power of the Dark Side [-1]. This works exactly like the Lawbreaker powers, but instead of referring to a broken law, they refer to the Emotion that lead to the character calling upon the dark side. So you could have Power of the Dark Side (Rage) [-2], Power of the Dark Side (Fear) [-1] etc.
I haven't seen it played out, but it would get a player nicely to really think about how he is using the dark side, narratively, and not just for the +1,+2 or even +3.
You had a couple of great ideas up there for a force system itself, here's me hoping some of you who are really good with the system figure out a good way to handle it, as I am still kind of new to FATE itself.
Cheers,
darkseph
