"Unlike the Empire of Japan, the Reich makes little use of permenant puppet states or protectorates, directly absorbing worlds or states directly into its national body over time with justification presented by the Constitution and national policies. Had the Imperium of Deutschland succeeded in maintaining control over the New Weimar Republic, it would have been reintroduced into the Reich completely." -- From your wiki article on the GGR.
I've not read your whole history. I will say it is very long and appears to have been laboured over for many long nights (and many more cups of coffee... or beer... vodka... Frankenwein... etc) and as a writer, I applaud your work. But (bearing in mind I've not read your entire history), as a German historian, I am curious as to how you have created the GGR, or I imagine as it is more properly abbreviated, GDR-- Großer Deutsche Reich... conveniently, the same initials in English of the DDR, or former "East Germany". *Ahem* That aside, the GDR/GGR does not use puppet states? I can only assume the alien war must have dramatically changed Nazism and the administrative format of the Third German Empire.
Also, if you are using a Windows OS on your computer, turn numlock on, hold alt and press on the numpad 1, 2 and 9. ü Führer
While this looks like a very fun mod and I likely will try it out (all depends on if I happen to stumble onto the forum and see its release). I just have to question your characterization (which, ultimately, doesn't really change gameplay) of one, maybe two factions. Nazism is not a safe subject to dabble in. I will assume that the space commies are descended from their viscous and brutal (often more so than the Nazis) commies under Joseph Stalin.
To wrap up, I just want to be clear: I am not saying that this mod itself is bad, infact, I look forward to amazing capital ships I do, however, question the character, the back story of it. It's probably too late to rewrite this faction (though calling it the GDR would be more logical and possible... if not comical for us history buffs that will think of German communism). I just wanted to share my thoughts on the topic. Happy modding!