i like the system so far.
i HATE prohibitive resource systems, b/c they take the fun out of magic. and i have never seen a system which is not reduced to absurdity b/c of the needed refreshing system (like one-button-sleeping in NWN2) or is bothering the crap out of game play (like 'i dont have enough mushrooms for a much needed spell in the next fights so i have to grind like 2 hours just to be able to fight in the first place').
whats wrong with cooldowns that prevent using uber-spells more than once in a regular fight but let us use such spells in every fight? if there is a one-shot spell, nerf the spell but do not include a dump, silly and foolish resource system which nobody really needs.