What is the reason behind it scaling only from mag mag and crit? I don't understand the reasoning really. Can't you just reduce max resource scaling and bring spell and weapon damage so you get about the same scaling, it's just unnecessarily strange in my opinion, there is no reason why it should work like this, also i am pretty sure it does not scale from % damage buffs and debuffs like major slayer, but not 100 % sure about this one.
Making it scale from max mag and spell damage/weapon like most other skills would make this skill a bit more versatile, it's already a good skill, but yea, doesn't make a lot of sense in my opinion.