I don't consider AoE damage in damage totals for the reason that it's situational, and that always there's going to be one target that's the concern.
But that is what spell choice is all about. I can't use fireball against a single guy and then say its weak. I should be using single target spells. As a wizard I have the ability to use the right spell for the job, so if I'm not doing that...its not a problem with the spell.