The moment someone says, "I use Assize for damage" they would immediately be ruled out of the hearing to determine whether or not WHM actually needs this. There are a few reasons for this.

The first (remember I am posing as a dev in this scenario), I couldn't care less about your ability to do more damage. Second, the ability also restores HP to the group, and MP to self. I would need to know why you feel WHM also needs to have another charge for those resources. And last, if determined increased access to those resources is actually needed, then why it should come in the form of a second charge instead of just increasing how much it returns being that it is already on a 45s CD.

Then just for sport, I would probably ask why you feel Assize needs to cause damage at all, since your AoE is already covered with Holy 2, which also brings mitigation making it one of the most effective AoE abilities anyone has in the entire game with the GCD and your nigh-infinite MP pool as its only required resource. Then I would probably conclude by saying to just be thankful that you have it.