"Divine" Damage

This is something I thought about when I was stacking magic resist against an AP team in ARAM. Essentially what it would be is that turrets would deal this "Divine" damage, and it would deal reduced damage based off of some sort of algorithmic combination of your armor and magic resist. What you could do then is have the turrets have a bit more of a punch with each shot, but tanks would end up having just about the same reduction of damage as they do now, even if they stack magic resist.

Thoughts?