Well atm they are free hps. After the pre-combat shots they dont do anything in the fight except take a hit. So as a defender unless its clear im winning the first hits go to the AA, they are dead weight at this point.
When they can return fire every round against planes ( might want to keep the @1 because they target units ) then it might give the defender a reasonable choice.
I agree. I thought when you said that you were referring to the version with your house rules, not the out of box version.
IMO they represent flak88 batteries, a bit more specialised AA guns then the divisional version but a lot weaker then the static stuff that defends ports/airfields and the likes.