As fire, she didn't run out of mana fast, lasting almost entire heroic boss fights without even the mana emerald. As arcane she used the emerald, a mana potion, and usually the channeled spell to regain 60% of her mana each boss fight.

Thanks for the suggestions on the spell hit. I believe I have a piece of gear or two with it, I'll switch them out and see if it goes up. She does have all the fire damage talents. The extra points from the "deep fire-Icy Veins" spec went into the stun for fireball. (I'll take any free stun I can get in heroics - I don't use CC at this point.)