Last game I played someone tried to use prokets on a-wing's against me, I frustrated him by blocking and even though he eventually got two out of three off he only killed one ship with two proket attacks.
In the end my ships with three attacks far out performed his a-wing's.
Ordnance is unreliable and your better off with a three attack primary ships.
I've had a decimator take three prokets to the side and not blink then blow a ship away with a range one shot.