[@Centimane]

I'd go with A, but not B. Thats just a tease. If PCs can't have it then you shouldn't have it at all. 

Has anyone read the Kingkiller Chronicles? The magick in that series is interesting in that MANY people don't know it and the ones that do find it hard to use. Its only taught at the University and low level sympathy (magick) is mostly used for practical things (forever burning lamps, different colored fire, etc). Not saying that we have to use that exact system because its rather complicated... but I think its a good example.