Amen, Citabria -- nice collection of how arenas should look. WarBirds lost lots of its appeal with its dismal dreary blue-brown-gray too-dark vistas.
And as others have pointed out, not much point in modeling WWII skies too foggy or hazy or other bad weather conditions because planes often did not fly in lousy visibility, at least when they could avoid it.
In addition, as many of your photos exemplify, Aces High II should allow exterior viewing like the premier system in MS Flight Simulator 2004. Few if any pilots can fight better using exterior views than the usual interior view from the cockpit.
A whole new dimension of enjoyment would be added with prettier (yes, p r e t t i e r) environments and exterior views on line (not to mention the incredibly better still pics and mopics).