The historical problem is that when one side brought out a new plane it did confer an advantage, but the problem is that the game is playing 1914 to 1918 simultaneously, so your new pilots in Aircos are up against a plane that would come out long after their aircraft was retired.
I can hit the D8 head on but it takes some concentration, and is much harder to hit from a chute at any angle given the wing profile. In an all star match last night against five D8s at once, three of us held for a good while, but I wasn't anywhere close to my usual KDR, and guys that I can usually trade kills one to one with had a marked advantage over my formerly supreme SE5. I went high to chase a fu... I mean, a tactician of altitude, and coming down chased a laden D8 around banging away at close range. Total advantage in speed and maneuver over the laden aircraft, which may have had two bombs. At some points in the swirl I had my nose nearly touching the tail and couldn't get hits. That pilot is a damn good one, and well know to DF, so there's that, but it was only when I could cut inside and get an angles shot at the top of the D8 in profile that I could register hits.
I'm a pretty fair marksman, but that thing is tough to hit.
To someone else's suggestion though, the only Allied monowings were early aircraft, French, slow and badly armed, so not a good historical fit.
Possibly the answer is to date the scenario to start, only period aircraft enter, so no more than one or two class differentials between combatants, as would be more typical of the front.