[Lefty Hartnett]

Since the design work was submitted in the closing days of WWII, only a few incomplete documents have survived

Clearly an essential addition to IL-2 then. :roll:

There must be hundreds if not thousands of aircraft designs that got to this stage during WW II. Why is it that only German and Japanese ones get requested?

I see your point---but also the Germans really privileged innovation, perhaps more than other countries--and perhaps to their detriment.