Perhaps one of the doctrines or an ability for the Ostheer could represent the Axis satellite armies (Romanian, Hungarian, Finnish Italian, Slovak) and fascist volunteers from occupied Europe (Belgian, Danish, Norwegian, Dutch).
They definitely didn't make up the bulk of the German army, but I think their numbers on the eastern front were large enough to justify a representation in the Ostheer. Though I wouldn't go as far as calling it "necessary".
Just of the top my head, a few ways to represent the satellites through doctrine abilities
- Romanian oil: Temporarily increases your oil production or like "Resource Blitz" a large oil bonus added to your resource pool. During WW2 Romania's oil production was definitely vital to the German war effort. It's no stretch to say that a lot of German tanks on the eastern front ran on Romanian oil
- Hungarian Toldi: Call in a Hungarian Toldi light tank. This would be the equivalent of the Russian T-70. A fast light tank, useful in the early game but no match for heavier armor like the T-34. (Plus, it's pretty tank
)
- Captured T-34: Call in a T34/76. In the early stages of the war, German success on the eastern front allowed them to capture a large number of T-34/76's. Satellite armies would gladly use them as they were far superior to their own equipment.
Wiking combat group : Call in the equivalent of the American "Off-map combat group", but with armor. The 5th SS Panzer Division "Wiking", was an armored division made up out of volunteers from occupied Europe (mostly Danish, Flemish, Dutch and Norwegian). It was considered an elite panzer division.
I just realised I didn't add anything Italian
Captain Corelli's mandolin:: Call in a squad of Italian infantry costing very little manpower. They play music and seduce Russian women, lowering Russian manpower rate because of lower birth-rate.
