I'd love German voice acting, too, but I guess it would make the game a lot more expensive.
Beside money logistics are another thing. I don't know if Larian has infrastucture of a major behemoth like EA or Activision necessary to do casting and recording in multiple countries they are not based on.
Just for the record: Do you know who was in charge of BG's Polish localisation ?
A small studio called CDProjekt

Of course.Another reason for them to do Belgian languages only. It's already more languages than most countries right at your disposal.
True, it would please the German, French and Dutch community, which is already a large part of Europe, so I'm all in favour for your suggestion 😉.