Somehow, I don't see the soundtrack (in FLAC format if I'm not mistaken?), behind the scenes stuff and an entire campaign map, as nothing. The official page lists the Imperial Edition as being availible as an upgrade. I would assume this would extend beyond just GoG.
In any case, I just really want it, and hope that the devs can/will do something about it.
It is, after all, more potential Money for them.