Okay, maybe a couple of suggestions here...
1) I would think that spells cost END, even the Detects. I would remove the Reduced END modifier on the spells. They'd cost a bit less, or you could get a little more punch in them.
2) I agree with Starwolf on the RSR limitation. That's sort of been a little peeve of mine with some systems, that magic will always go off as planned. (Just for grins, a Side Effect for some spells here and there would add to the dangers of magic.)
3) You've got some of the more standard limitations in there, namely Gestures, Incantations, and Concentration. I'd almost want to throw in Extra Time, at least Full Phase, especially for some of the more powerful effects. Giving it ET: Full Phase would still make it quick; the caster just can't do much else in his active phase.
As stated previously, it's your system. Do with it as you will.
