Interested.

How I have done magic is that it will drain off the natural stamina of an individual. The effort it would make to do something (i.e. light a fire, life a rock, etc.) would be taken from the user to do it magically. Which is a heavy restriction, especially in battle. I usually have a system that allows one to "store" their energy, but that could become too powerful in a nation RP (i.e. government forces mages to store all their energy into giant magical death beam that wipes out another country). So, it could be like that. And, if that is added onto the already instability of magic, then it would be fairly restrictive without making it useless as a form of anything.

Of course, just a suggestion. Honestly, in a nation RP, magic doesn't really have to be prevalent. My nation would have a very minimal amount, and I'd likely rarely even mention it unless it came up as a plot-point.