Here's the problem with AvA:
The very low numbers mean the only way to really proceed is to basically use it as DA. That means the two best "duelling" planes out of each given set get upped for duelling style encounters, and other planes and flying styles gets short shrift. This can only hold many player's attention for so long.
Let me give you an example, lets look at a conceivable abbreviated set for MW ETO. Allies: SpitIX, P-47D-11 Axis: 109-G2, Fw-190 A5.
Because the AvA will essentially be low alt 1v1s or 2v2s most of the time, the latter planes will get short shrift in usage most of the time. P-47D-11 vs. 109G2 1v1 at low alts with competent pilots is just not very amusing in AHII, nor is 190A vs. SpitIX. One might as well just limit the set to 109s and Spits (which would be at least a slight imbalance in favor of the Allies anyway) or maybe just P-47D-11 vs. 190s (which would be more balanced, but still not quite). BTW, balance in terms of dogfighting performance for player fun vrs. putting what planes were historically actually there in the set will ALWAYS be a daunting problem for AvA when numbers are this low.
To give each and every plane its place, and to give that historical feeling that alot of players want out of the AvA, you need more numbers and more historical engaging conditions. For instance, when engaging in squadron numbers at 25,000 feet, P-47D-11 vs. 109 G-2 is suddenly alot more interesting and sporting. 190s suddenly make more sense with more altitude and more numbers, especially if there are bombers to be shot down. I hope what I'm getting at makes sense.
How to accomplish these things, I dunno. Maybe Jimson's idea is the way to go.