I would not AA in H4, but if 343 will decide to use it, please insert it in only one playlist (not team slayer). No AA in all others playlist!
Armour Abilities have had their fun for now. Custom Games, Campaign, Matchmaking you name it.
But they are a Reach exclusive and are what made the game different from the others. I say leave what made Reach to Reach. We can always go back and play the game again if we wish to revisit the past.