Heehee...I grew up on that cartoon, it dominated my childhood.
Well...what about snake eyes and storm shadow? Were they japanese or what? Did they ever show their faces or even speak? I dunno, see, you couldn't have had a frenchman in there, I mean that's just ridiculous to consider, and Germany at the time was divided into west and east and you had the Russians in there and that would have been awfully complicated for a cartoon.
The motto was 'A Real American Hero' after all.