My current players, especially Tim, would hate the paper work required.
I got to play a War Troll Runemage, set in the Game of Thrones world ran by Matt. I used Herbal rules for open list, Corpist for closed and Nomenist for base list. I really enjoyed the experience. The occasional limitations were a fun part of the story, creating frustration, concern and a tendency to use a long knife on corpses, which is very frowned upon by the manly races. Men of course are typically to consumed in their petty concerns to see the bigger picture, such as the benefits gained from a freshly stilled heart. Really though, of they think their silly dead are so sacred, the gate to the grave yard shouldn't be so small it can be stepped over.
One of the neat parts when using these skills is the new lore and seeming depth of knowledge the rules create in the game world/setting. These skills can be introduced as secret lores or existing lores explained. PC's will be very interested in jewelry worn, not just for wealth, but as a hint as to what sort of magic the wearer mat be a master of. A fetish wearing anybody will generate respect, curiosity and even caution.
A result is a new skill set non spell users will develop, in part to reflect their knowledge of the world they live in and also because their is a tactical advantage to be gained, or a weakness to be compensated for if you prefer. Helps disguise/duping/non magic users to fake being a spell user too.
The real work for the GM is providing the materials needed by the PC. Most are available in the market, but some may require expeditions into wild lands or other planes or the crystalized blood of a wounded Gawd, etc. Primarily, it requires a mature gamer not afraid of a restriction or three and plenty of record keeping. It ain't for everybody.
