That makes... next to no sense to me, sorry. A new cover means that there is a new cover. I don't see any conspiracy behind it. If anything, I'd go as far as saying that at the present moment a new art is the best thing you'll see for a very long time when it comes to "new content". They will not surprise us with new content out of the blue. This is not how CDPR works, you should know it by now. Even patches are advertised with interviews and articles prior to release! They would never stealth-release anything.There is actually an option 3.
That the new cover art will be used to release a "new" game/expansion.
Maybe will be the next-gen patch, but you'll have to pay it.
Seeing CDPR greed, this will make actually sense.
New art, new expansion, new price