"Weapon Storm only does the damage listed in the spell," which is what exactly, because the spell doesn't list any damage type other than, "the same type as the weapon," which is either piercing or slashing depending on my mood since it's versatile.
... and no it doesn't, 4d12 is roughly 26 damage on average rolls and a fireball heightened to 4th level is 8d6, which does 28 damage on average. I'm basically gimping myself by not using fireball, which also doesn't require me to get close, which raises the question, why ever bother with the spell at all?