If game balance is a factor, the A-Wing sucks. It needs something to make it better. It is absolutely not balanced. You could run a full squad of anything in the game except A-Wings and hope to win.
That's ridiculous.
You are missing the point entirely. 4 A-Wings might work or it might not, but 1 or 2 in a list with other tools is excellent. Combined arms works in this game. Why does everyone want to make spam lists when they theorycraft?! Don't forget to arm them with upgrades. PTL is amazing on an A-Wing. Missiles are also great.