"Too many planes that actually participated in the conflict that should come long before the might have beens, had no impact on the war types. "
This is only relevant for people who are actually interested in somehow re-creating WW2.
IMO, since the MA in no way represents any past war, plane additions should be chosen more for usefulness and how well they "fit" in the MA than worthless factors like nationality or WW2 usage (and if I had my way, there'd be several different arenas with different eras of airplanes available, instead of a single MA). A better argument against the "uber" propeller planes like the Sea Fury and the Bearcat (especially the 20mm ones) is that they're simply "too good" to make for good balance against the majority of piston-engine fighters.
Personally, I view a transport as the single biggest plane type AH2 needs as an addition since it's a much-used type with only a single model to choose from currently.
J_A_B