Hey Softmints, This might just be me but the concept seems to lead back a bit to Pure Damage that is present in several games, the damage is usually lower than either of the other 2 standard damage types and since Runic Damage likely is lower the best way to negate (a niche form of damage) would be to just get more life and to instead out-soak the damage ignoring the damage type completely (due to a low pool of heroes having this type of damage, also a similarity to pure damage for the most part) the difference between Runic and Pure being that in your case Runic seems to affect objectives which in most games Pure wouldn't.

Also, another topic suggestion I have which might be intresting to cover would be something about design philosophy related to LoL's descision to ''kill'' switching top and bot lane by adding extra armour to top lane's tower.