I am considering starting a Pathfinder game, however before I do this I would like to brew-up some house-rules on the use of magic for a "low-magic" setting (think Conan or A Song of Ice and Fire) that make magic more unpredictable and dangerous in practice.
My ultimate goal is to a: add more balance between caster/non-caster classes, b: add a mechanical component to the flavor that magic is both dangerous and powerful, and c: avoid adding too much unnecessary crunch. I am not sure I want to ban magical classes outright, so the ideally I don't want to completely nerf spellcasting or frustrate players with arbitrary punishment.
Edit: If you think another system would work better for this please explain why you think so - I'm not super familiar with systems outside of d&d. My main interest is really how to add a mechanical element to the idea that magic is dangerous/unpredictable, while remaining fun to play.
Some of my ideas:
Implement a Call of Cthulu-style sanity system for the use of spells: the greater the spell level relative to caster level, the greater the risk to your psyche? Perhaps casters have sanity-resistance for spells 1/3 their level? This has the potential to be clunky, and I'm a bit worried about arbitrarily telling players how they have to role-play their characters.
Or maybe some variant of the Wild Magic rules: I'm a little more cautious with this one, as the magic surge rules in 3.5 seem obnoxiously unpredictable, and I don't want to have to consult four different d% tables every time a spell is cast. Maybe a card-draw mechanic on a d% roll less than 10x(spell level - 1/3 caster level) + concentration check? The cards would be 2/3rds negative, 1/3 bonus metamagic effects?
Or maybe just restricting PC casters to a certain class?
Any ideas for how to do this or concerns you have that I might not have considered would be greatly appreciated.