12x .50 cal? Where did you get that?
, triple 20mm are fine, in fact F-4 with single cannon is useless.
The biggest problem I have with the game right now is the "upgrades" system, having to grind an absolutely useless aircraft for loong ass time before it gets any good just ruins the fun. I see no point in progressing up the tree now, you're just being punished for buying a new plane. That and the fact .50 cals are useless and weak, those are the worst problems right now IMO.