S! Dowding
The Arena would not be dull and boring. When people have clearly defined objectives, action focuses on those objectives and you get intense combat. Because of the complexity of a historical arena, the interactions become much more compelling, simply because there are more options tactically. Your opponent can succeed in multiple ways, and your choices to counter his moves are many.
For example, the Germans can destroy the Allied bridgehead by either:
1) Conducting a land offensive which drives him back into the sea
2) Cut his supply lines through an Air Offensive by destroying the convoys between Southhampton and the Artificial Harbours through air attacks.
3) Do the same as 2) by destroying the Supply Convoys through Naval and Submarine attack.
4) Protect your V1 launch sites well enough to allow sufficient numbers of them to be launched into the Allied ports of Southhampton and the Mulberry Harbours at Normandy to destroy the Port infrastructure.
Plus any number of other combinations of the above.
And the Allies would have as many options.
As far as aircraft choices, the Luftwaffe, U.S. and British planeset makes up by far the largest percentage of the existing AH aircraft stable. Nearly all of those could be available. And you could use the Italian aircraft too. Because it was operationally possible for the Fascist Italian Air Force of Northern Italy to participate at Normandy if the German Command had deemed it imperative for them to do so.
Someone mentioned they wouldn't want to be fighting Tigers with Shermans. To start the Tiger wouldn't be available in any large numbers. The Sherman is definitely not as good a vehicle in a straight up fight in the open. (Although a Sherman Firefly will punch a hole in any German Tank, its 17pdr gun was actually better than the 75mm high velocity the Panther was equipped with) But Tank combat isn't just a question of bow to bow gunfights. A Sherman is a lot faster than a Tiger. The U.S. model with the Gyroscope was actually capable of firing on the run. And the Sherman was equipped in the second half of the campaign with what was called a Rhinoceros bow attachment which allowed it to burst through the Hedgerows. The German Tanks had no such device, and were restricted to the roads and any road entrances to the fields. The U.S. tankers were able to head off cross country and to bypass and cutoff, or come up behind German Tanks.
Actually my personal favourite historical arena would be the Malta one, which had tremendous air/naval interactions, both at night and in the day. But it doesn't have a ground aspect, unless it was extended into '43 with the fighting in Tunisia and the invasion of Sicily. But those weren't the most interesting periods as far as the siege of Malta was concerned.
AH could also do a Okinawa HA almost as easily as a Normandy one. Okinawa is a relatively small island, so the combat area would be manageable. A lot of the aircraft exist already in AH, but you'd need to build quite a few Japanese planes, plus of course all their tanks and the U.S. models, plus various ship types.
History allows you to design a layer of complexity into a game.
