My only issue with AA's is the pacing of the game when they are introduced. It's a lot quicker and 'arcadier' when you are relying on your gunning, strafing and nades to fight to power weapons. AA's seem difficult to balance and nail down - they also encourage horrible tactical plays (I'm looking at you armour lock). I can see AA's being used effectively if they are well thought out - a combination of both may work if certain AA's are removed.
Plus it normally only leaves two key areas on the map to dominate - I liked the idea of rushing camo/over shield at the start of a match while everyone else rushed the sniper/rockets and then using the physical advantage I have gained to try to take control of the power weapons.