S! Hazed
This would be my opinion:
We already have perked aircraft, which change with each planeset. That should stay the same.
Next you fill the map with targets which reflect the historical realities. These targets were generally supply related in most situations.
And you assign victory points to the destruction of these targets, as well as penalizing with supply shortages the side which lets its targets get destroyed.
If we are talking NorthWest Europe, say pre-D-Day invasion, the following realities were in effect which would affect the design of a Scenario:
The Allies wanted to get ashore and create a second front. To do this they had to weaken the German Atlantic Wall defences. The way they did this historically was to destroy the supply infrastructure which supported and moved the German troops which would resist an invasion. This was primarily the French Railnet. Between January and June '44, the Allied Tactical Airforces (Medium bombers, and Fighter bombers) destroyed a large percentage of the German and French Rail Rolling stock, and severly damaged the Rail marshalling yards which supported and repaired the Rail system. When the invasion came, the Germans in the Front lines were way behind in creating defences, lower on Fuel and Ammo supply than they wanted to be, plus the Panzer reinforcements which were intended to be sent to the beaches to drive the invasion into the sea were unable to use the Rail system, and had very little fuel. Plus they were under constant attack as they moved up to the front. They got there way too late and the Allied buildup proceeded faster than the Germans could put their defences in place.
We could simulate this in a historical setup by creating Rail lines in France, Belgium, Holland and Germany, and having the destruction of Trains affect supply and victory points.
At the same time as they did this with the tactical airforces, the Allies targeted the German Fuel production centers. The idea was, if the Germans can't get to the battlefield by train, they'll have to drive. No fuel, no fight. The Allied Heavy Bombers escorted by long range fighters, went after these targets. That forced the Germans to defend them, and the resulting battles ended with USAAF dominance.
We could simulate this by placing the Factory and City targets in the appropriate historical locations, making them targets of importance which affect supply, and placing a victory point value on them. The Allies would have to destroy or damage enough at one time so that they reached a victory point level. Repair would be slow, but if the Allies didn't keep up the pressure, the facilities would be back up.
The Germans would win by preventing the Allied victory conditions.
I would also restrict the use of Heavy bombers in this. I know it's heresy to say, but I wouldn't allow B17's or Lancasters to hit Airfields, Vehicle Bases, Rail lines or other tactical targets which historically the Heavies didn't have the accuracy to take out. Those would be strictly targets for the Mediums and FighterBombers, as they were historically.
The Scenario would go for a Week or two. At the end of the period, the points would be totalled and a victory declared.
I think it would also be a good idea to have players intending to participate to pre-register on the side they want to fly. And they would only be able to fly that side.
Also, the balance in a Scenario like this would be better a little in the Allied favour. It is always easier to defend than attack. And the Allied would be flying a lot of bombers and Fighter bombers.
Probably 55% Allied, 45% German.
But you could also just leave it up to the players to decide.
You could also give Germans targets which they had to hit. (Hitler was always insisting the Luftwaffe bomb England)
Maybe they'd have to hit targets in Southhampton and London. City targets. If they didn't hit them, they'd lose victory points. (Hitler would send the Commanders to a posting in Norway... lol)
Plus there were British Convoys running from Southhampton Southwest through the Channel out to the Convoy routes to the U.S. and Canada. The Germans could have them as targets.
And there were German Convoys in the area of the Scheldt Estuary and Holland which the Allies could hit.
Lots of possibilities.
If you want a really detailed scenario have a look at my Med Scenario posting, ("Combat Theater Lovers...") which I posted on the Combat Theater board too.