Originally Posted by Yitzi
The problem with this is that it makes rocket tag play even more mandatory than it already was, and in particular hurts defensive (high-AC, low-DPR) fighters.
If you define rocket tag as over 150 damage per round from an entire group, then sure.
I think you would be VERY hard pressed to find a group (monster or PC) that as a whole couldn't deal the damage to get through the armor HP.
As for high-AC low-DPR fighters, this is better for them than armor as DR at least, as here their damage stacks with everyone else's for bypassing armor, with DR they lose a much larger chunk of their damage than everyone else, so it hurts them more.
It may be worse for them than the regular method, but let's be honest: Low damage high defense turtles are already a bad option. Making it a little worse honestly does nothing bad to the game, as that is an option that can and should be improved via other means.