Make each country have a goon, a fighter, an attack plane, a jabo, and a heavy bomber, then change the arena to the style in FA. There'll be an infrastructure (trains, truck convoys, rail stations, railways) to attack for those who love mudmoving. As long as there's air, there'll be dogfights. Add more factories that are capturable. Make server-controlled tank attacks. Add small towns to the map. And if a certain percent of a town, airfield, railstation, or factory is destroyed (including structures and not acks), then a server controlled tank attack is started. Or just level the field acks and send in a goon.
Divide the arena into 6 countries:
U.S.
Great Britain
U.S.S.R.
Japan
Germany
Italy
You'd only be able to fly planes of a certain nationality, depending upon the country you are playing for--eliminating spit vs. spit fights and niki vs. zeke fights.
So just convert the MA into an arena that will satisfy HA-goers and MA-goers: one similar to the arena in FA--and it won't be Axis vs. Allies--it'll be country vs. country.