Read some of Kershaw’s works in particular and you’ll get an idea of what a mess Nazi Germany was administratively. It’s hard to believe any professional historian would believe it was efficient at all, now or 200 years in the future.
Well, it’s possible Nazi Germany (or the 20th Century, for that matter) wasn’t John Gill’s field of expertise.
Of course, that doesn’t explain why his attempt to graft Naziism onto Ekos was apparently so determinedly micromanaged that a uniform manufactured aboard the Enterprise (presumably drawing upon accurate historical information) blends in perfectly among the Ekosian knockoffs. If Gill had access to that degree of historical precision, why be Ekos’ Hitler? He could more easily have been its Edison[sup]*[/sup], “inventing” technologies to dramatically improve the Ekosian economy and standard of living.
Hey, maybe that’s why Ekos’s version of Naziism was also doomed to failure - Gill was so obsessive-compulsive about making everything match the Earth version (even down to uniform standards) that nobody could make a move without his approval. The “serpent in the grass” character of Melakon isn’t really needed at all, though it is mildly amusing that Skip Homeier played both a Nazi and a hippie on Star Trek, and both of them were jerks!
[sup]*[/sup] Yeah, yeah, I know, “not much difference” …
On the other hand, a lot of Americans volunteered to serve in foreign forces before 1917; Ernest Hemingway, f’rinstance. Some even fought for the Central Powers for ethnic or political (mostly anti-British) reasons. So Ellison’s veteran *could *have been wounded at Verdun, fighting for either the French or the Germans.
I wondered about that myself. 
Actually not - Germany was obliged by treaty to support Japan if it was attacked, not if it attacked someone else.
ARTICLE 3. Japan, Germany, and Italy agree to cooperate in their efforts on aforesaid lines. They further undertake to assist one another with all political, economic and military means if one of the Contracting Powers is attacked by a Power at present not involved in the European War or in the Japanese-Chinese conflict.
Absolutely. There’s a similar situation on Galactica 1980 in which a fellow with time travel and the goal of improving Earth’s chances against the Cylons decides to go back in time to aid Germany, rather than (say) aiding the country with a huge industrial base, demonstrated ability to accept refugees and incorporate them into its society, and without a nutcase at its head.
My understanding is that really didn’t become widely known until Albert Speer got out of prison in 1966 and started writing about it and doing interviews (naturally painting himself favorably). His assessment of Nazi Germany died from the neck up meant the shoulders below were pretty good…and that’s what historians largely saw for 20 years. Plus if you win, you will emphasize your victory by saying how tough your opponent was