I've had thoughts that magic would operate much like how Alchemy and Alchehestry does in Full Metal Alchemist. You know, tons of hyper-compressed mathematics to achieve desired supernatural effects which take advantage of the basic elements; and that's basic magic. More advanced magic will screw with time/space, and beyond that is God's territory.
You know, for example, why else are there all sorts of runes, pentagrams and so forth when magic is ever mentioned, as well as certain chants and such? What would be the odds that the chants or oddball names are just mnemonics of formulas and the 'grams and runes are variables and ways of structuring formulas into a managable and easy-to-use crosshair? With capable enough minds, they would no longer need to be drawn first nor spoken to be activated, and can then be cast in mid-air and so forth (IE-drawn from the mind). Those with photographic memory would be extremely dangerous in this territory.
Magical weapon/shield engineering would be a fun territory to work with. The lowly staff can have pre-engraving of everything set in a way, all that would be necessary to use it is thinking of the activation symbol (usually etched on the most visible point of the staff to the wielder). With smart application of all kinds of runes and symbols and crap, one can essentially turn a magical staff into a magical sniper rifle or shotgun. In this day and age, we can skip past the basic magic, and make ourselves magitek equipment and such. The only other setback to magic casting would be that it would be both physically, mentally, and spiritually draining if excessively used.
Funny enough, I think we're plenty capable of it without any kicker. It's a dormant ability we all have. An age of magic had to exist some time ago; we locked ourselves out after a great war broke out, and just forgot about it, and with good reason.