Thornmail Too Restrictive

Considering the existance of:

Wouldn't it make sense to just make Thornmail apply grievous wounds upon being dealt damage by an enemy? Tanks currently have no real way to prevent the huge amount of healing that those champions receive and it becomes counter productive for them (the tank) to even go near them. I would take this over the measly 15 damage being dealt to the attacker per auto post mitigation.

I would be fine with Bramble Vest keeping the on-being-hit-with-an-auto-attack clause, as to not totally shut out these champions too early, but later on I really don't think that Thornmail is doing its job in matches with any of these champions. ADCs sustaining isn't nearly as much of an issue as these guys half the time (looking at you VLAD).

In recompense though I would also be okay with lowering Grievous Wounds to 35%, or even 30% to match Spirit Visage. I don't want these champions gutted, I just don't want tanks to feel punished for going near them.