This is a thing I've been thinking about recently. Armor is one of the harder things in the game to play around. The only way to actually remove it is damage, while other things like minions, health, and weapons have Speed Test Scrabble Word Finder Solitaire alternative methods of removal or transformation. Add in that some classes historically become oppressive when they can generate too much armor, like Druid or Warrior at points in time, and it makes sense for the mechanic to have a some sort of counter play added.
I agree a counterplay would be nice, for example in K&C where the warrior had to spend his armor for AoE, that imo was balanced.