Some things I think would be cool would be a large magazine machine gun shotgun that covers a decent area with obscene amounts of weak pellets for the Reaver for anti infantry, with the current airhammer being retooled as a general purpose weapon for close range since that's pretty much what it is in my opinion, though I've been using the stock gun as of late since it's the best at long range so recent changes may invalidate that.
To compensate I'd give the Mosquito: 4, 6 or 8 wing mounted anti infantry machine guns that you can modify the zeroed in range by pushing a button. It would be a good idea to make the 4 gun loadout be higher damage and lower rate of fire per gun than the six or eight gun loadout. A real life example would be the difference between a few of the most popular in their stage of the war loadouts of some WW2 fighters, the Hurricane (eight .303 caliber machine guns which are close to rifle bullets), the Mustang (6 50 caliber machine guns), and the Typhoon (four twenty millimeter cannons). That way if you are on the wrong zero range the bullet streams crisscross on your strafe run and cover a larger area with bullets for suppression, or you could get the zero range correct and have faster TTK due to the bullets landing. I'd suggest making the rifle bullet equivalent and the 50 caliber not damage armor and the difference between the two being rate of fire and damage, while the 20 milimeter is basically 4x forward mounted bassilisk. The downside to the basillisk loadout would be greatly decreased maneuverability due to increased weight, if it were my choice. That way it would be pretty terrible in dogfights but it would be good for ground support.
VS I dunno, maybe an anti infantry laser. If it could be like a solid beam that you can 'drag' over infantry for light hitscan damage that might be cool, especially if it was tied to some kind of launcher, either infantry or vehicle, that shoots straight up then tracks to the spot the laser is aimed at. That means they would have to hover a scythe to guide the missiles.
I'll suggest all these suggested new weapons do no damage to heavy armor and that they be badly subpar in dogfights against other ESFs armed with appropriate anti air weaponry as the tradeoff.