| My fix was to switch it to a Resist value (equal to your Con mod) against melee and close damage, and the damage bonus only applies to the one who triggered the resistance, only on your next attack on them, and only if you don't take damage in the meanwhile. Then behind the screen when I've got minions whose attacks ought to penetrate, I'll list that (4dam, 1 vs the Battlerager in our group).
This is actually more a simplicity fix than anything... the minions tweak gets rid of complete immunity issues, while the damage bonus is made more specific in order to tone the whole thing down, but the primary effect here is that done as a resistance value there's much less shuffling of tempHP counters. Which was honestly my biggest problem with it.
However, I like the solution proposed by Garthanos above; very elegant. | 
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