I'd love to see a unified, modular toolkit approach, where designers could simply create units by matching men with weapons, uniforms and equipment to create basically any force from 1930-1950. Want some Serbian partisans armed with a mix of old rifles, ex Yugoslavian army equipment and a mix of captured Italian and Romanian gear? Here you go! Fancy pitching them against an understrength company of second rate Slovakian gendarmerie armed with old German equipment and French armoured cars captured in 1940? Tada!