OP Classes?? umm no its BALANCED

Airstrikes are kinda ok, they could do with a little longer detonation time though, perhapsa a slightly smaller area of effect but nerfing them to much will just make support unattractive to play. Airstrike is pretty much the Support's main attack, shotgun is not always reliable and draingun kills to slow against a good shot.

But well people will always complain about classes that kill their class the easiest regardless, every classbased game has this and in all fairness is understandable.

All in all though i'd say the game, from launch, is really well balanced, much more so then any other game that had different classes against eachother.