I think for the general purpose magic(rituals and stuff, rather than combat/minute time evocation), you could take a leaf from one of the more flexible magic systems like Mage as well, saving the quick and dirty magic for proper spells.
The casting stuff itself, particularly in combat, seems seed/point based, with foci being useful for most magics(particularly, combat magic, where every bit helps). The foci themselves seem to be craftable by any decent spellcaster, though making one of any strength requires real talent.