Please, make magic system deep, complex, and powerful. Spells should not be limited summon and direct damage. When in battle mage running around, waiting couples recharge direct damage spells - it is a bad system. Should be defence spell (not -15% from damage!) versus different threats, spell like time stop, teleport and so on.
I think the best magic system was in BG2. Please do no worse.
Sorry fo my bad English.