The "which side will win or has better equipment" thing IMO could be mitigated and controlled by rules/eny/etc, there are many options with regards to this problem. Limiting the numbers of the AI formations, etc etc - so many possible ways to balance the sides out, if you're looking for gameplay balance and fairness as opposed to "historical realism". Heck, you can have both, some nights for example run a BoB or East Front map with realistic squadrons and numbers and such, and other nights have the game balancing tools in effect.
To be specific, this is what I was thinking of: Recently I've been yearning for the experience I used to "feel" in older games like Aces of the Pacific, and even Falcon 4, where you played a campaign and felt like a small cog in a huge wheel. I recently bought both of the Battle of Britain flight sims, Battle of Britain 2 with its superb new patch/realism mod, and Il2-Cliffs of Dover, which too has undergone a recent patching/modding, and is much better than when it was released.
While both of these games are great in their own respects, BoB 2 especially for that feeling of huge formations of L/W bombers and British fighters swarming about, they both lack that "Aces High 2" feeling of actually FLYING a simulation to me. What I'd be shooting for with my wish list request would be an experience that BoB2 or even Clod provides in terms of a single player campaign experience, combined with having the option to have AI planes "taken over" per se by human pilots a la massively multiplayer fasion (shameless Dale plug), along with AH2's superior flight model and game fidelity. Again, it would be like an FSO experience that could be jumped into at any time by any player. It wouldn't take away anything from FSO or scenarios either, as the whole point here is to have something that doesn't require the intense planning and participation required by those events, yet recreates their experience and greatness for players wanting something like that at the tip of their fingers.
edit :
The biggest drawback of AvA in my experience has been that 1) No one is there and 2) Almost everyone is on the same side.
Exactly Sax, this is one of the reasons I don't fly AvA, even though it SHOULD be rights be the place I'm most interested in. I think the idea I'm spelling out would go a long way to fix this, as even if there was nobody else online with you, you would still have a great time as there would be TONS of AI stuff flying around, with pre planned auto-missions and the like open for anyone to join, or even create and populate with their own AI wingman. If other live players happen to join in, so much the better, the more the merrier right, and you could have your real life squamates populate several AI squadrons, and have just a few of you lead dozens of planes into action.
Just run "scenarios" (IE, Guadalcanal campaign, or BoB, or Defense of the Reich, or Eastern Front) with limited plane sets rather than a beginning-to-end RPS.
I didn't mention rolling plane set at all, and it's not something I like in any shape or form myself, so I agree with you, and that in fact was the idea I thought I was getting at - just run scenarios in this "new" AvA arena for a set period of time, then change to a new one. There would be no shortage of participants wanting to write new AvA AI arena setups I'm sure. It would be like being the CM of an FSO/event, but you wouldn't be limited by numbers or participants, as you could create large numbers of AI formations and flights of whatever you wanted.