Let's say that, as in Fatherland, Germany wins WWII and goes through a Cold War with the US. In 1990, like the USSR, it finally is forced to break up (presuming they don't go on a typical Nazi stance of never giving up). This poses a number of problems:
Formerly German lands are now at least partly "Germanised" but still have a significant native population. How do the Germans handle this?
There is a Russian rump state behind the Urals. How do they approach the newly liberated Russia?
How are the borders of Germany proper drawn?
Can the Germans expect any united front against them now they are weaker?