The problem is that it is contradictory that his direct shot causes more damage than his manual dispersion shot. That is, if your ability is manual detonation, then your critical damage should be less than this. So, everything will revolve around how skillful you are to manually detonate the shots and not feel a bonus of damage when you shoot directly at an enemy.
To be honest, those are my favorite characters because they are the ones that can do the most damage once you have mastered these characters, but I admit that if they are something broken.