Skyrim's Official Deluxe Soundtrack (that super limited one, sold by Jeremy Soule himself; I've got one of these, with Soule's autograph btw) was published as 4CD SKU, with 3 CD's packed with music tracks and additional fourth with sound/musical soundscapes, called "Skyrim Atmospheres". It's even featured as a single track, with duration of 40-something minutes.
Can we hope for something like this, but Witcher 3? At least in digital form maybe?
The basic OST released with the game is great, but it doesn't contain everything.