The idea is this. Lets put something like hit locations into Fate. Now I don't mean that we should add in head and arms and all that jibber-jabber. What I mean is find the narrative locations(fictive locations) of your character and make those areas you can attack. BAsically I think we already have something like those in the five character aspects.
the question then comes down to how we can utilize them as locations to strike? What happens when you hit them? My first thought was to add in a stress track for each, but that would add a lot of bookkeeping without really altering anything significant. So then lets look at consequences. I think what I would like to do is remove stress tracks and just have consequences.
How would this work?
When you enter a conflict you declare what you aspect you are trying to alter. You make the attack roll. They make the defense roll. If you win they must either change the aspect or take a consequence(this represents a short term change as opposed to meaningful long term change).
Now this will mean changing a few things. Does your aspect represent a physical, social, or mental location of your character. This could be Items(physical), Social standing(Social), A rational Mind(Mental), or even stranger things. this would mean that most aspects you have would need to relate to how you can manipulate your environment(in a fictional sense).
Aspects also would be fairly permanent. you would be unable to alter your aspects at minor milestone anymore. Aspects then become core parts of your character that are very difficult to change, and only change via conflict or intense personal growth(a significant milestone or greater).
Another potential downside would be the speed at which conflicts are resolved. Combat is no longer about killing people, but without stress tracks it becomes very quick, no more than four turns at a maximum. Also we would need to change the extreme consequence. As it stands it changes a major aspect, and that is already a lose condition. I see the extreme consequence as taking the place of a concession in this system. It allows you to change your aspect rather than your opponent changing it.
I think this idea has legs, and I think with a bit more work it could be something really neat. As it stands right now though...I just don't know. Let me know what you think. Maybe together we can figure this out.