I think magic is kind of hard to use in OB. For ranged magic, I hardly ever hit anybody cuz the thing flies so slow and the enemy can dodge it. But once I hit, it doesn't do much damage. For "on touch" magic, the problem is once you get close, you have to perform some gesture to cast the spell, taking quite a lot of time, giving the enemy to hurt you and knock you back, in which case you have to come closer again - and the whole thing repeats.
My suggestion is, make the casting time (also cool down time) a variable factor, which depends on your skill level. For ranged spells, either make the fireball bigger, or implement some guided missiles.