This feature would add some more lead above the close airspace on a base. The field guns currently fire a slower rate than a 50cal. Add a rapid fire defensive gun capability increases the damage rate for attacking aircraft.
I met two ponies on my own, co - alt at 15k two days ago.
Both rolled and dived to their ack where the proceeded to circle the centre of their field. I killed one before ack tore me up and the other moron got the kill. Met the same two guys 20 mins later, same deal although this time it was ship ack and I got one shotted by a 5 inch at ridiculous range.
You want to up field ack levels I say fine as long as guys flying through it over their own field get shredded as well