Hi,
a premier release in Germany stems from Larian history.
Even though a Belgian developer, their first steps with CRPGs were in cooperation with German developer Attic back towards the end of the 90s.
Then with their "coming out",

, it was a German Publisher (CDV) who financed the game in the end and brought it to the shelves.
And now, after short liaison with Ubisoft for

, again a German publisher (dtp entertainment) is on the controls.
So it´s legitimate to say that Germany (along with the other major German speeking countries Switzerland and Austria) has become like the actual "home market" for Larian.
It feels natural for them to pitch their new baby there.
And after all, the other foreign language areas can just benefit from it, when the initial bugs get eliminated first and will be missing in the international releases then.
Hence the delay: fixing the bugs & wrapping up the console version (XBOX) = 1,5 months
Which leads me to the thought v1ctor already brought up:
In the other countries, given the diminished standing of PC gaming in front of the consoles, the XBOX will probably rather be their major release.
And that version, due to it´s special conditions, had been announced for a few months after quite early on.
Cheers,
Ragon