Hi. I'm strange. Kthnxbye.
Hm. Not really that bad of an idea.
Remotely, in my totally weird mind, I thought GF named B/W, well, B/W because of the storyline having strong concepts on good and evil.
So if they do a respin on an already visited region with Unova Pokémon, it could be done, but it will have to be targeted to an older audience. It would be like making people play Pokémon R/B/Y, but this time retargeted for older people, or for longtime fans of Pokémon who grew up with that region, and now is experiencing the continuation.
On the other hand, I enjoyed B/W mainly because it felt like playing Pokémon Blue all over again, with new Pokés, new characters and the sort. It put a novelty in all its nostalgic glory.
If they DID however do what you just implied, it wouldn't really be the same, it would be okay, but it's quite risky.