I like the idea of dropping the drain and having them do stun damage. It's hard for me to imagine fire doing stun, but the precedent is set of electric with every electric weapon in the game doing stun. Also, sonic doing stun is kind of the only way that makes sense for sonic damage to work, so elemental magic doing stun should be in play, too. That said, I'm not opposed to having two different kinds of electrical spells, one that does stun and one that does physical (lke stunbolt/ball vs. powerbolt/ball).