I'm inclined to agree, though on a bit of a different line of thought than you. With some testing with friends, we figured out that something like 10 points of resistance minimizes one point of damage. So that +100 resist from our spells is... useless. That's only -10 damage.
It'd be cool if either resistances were buffed or if the spells were revamped to resist damage from a certain source by a %. So reduces incoming flame damage to 75% or something? Maybe not that extreme, but similar.