I hope it's not a gwent app. I sorta liked it in witcher. But the game is way too simple for playing against other people.
Then again, I felt the same about hearthstone and people love that, so maybe I'm wrong.
Honestly, I didn't think Gwent's expiration date was longer than the game's length. It was a really cool mini-game, it fits that role perfectly, but its adoration seems like a bit of a meme to me; I think people make it out to be more than what it is.
Were people really entertained once they acquired enough cards (especially Hero cards) to steamroll every character in the game? It was only really challenging when you ran against an opponent who's deck was way beyond your expected deck strength (e.g., Blacksmith girl who could onslaught you with summonable monsters or doing the tournament early), but that was because the game hadn't given you the opportunities yet to get enough quality cards to even the odds. If you were losing outside those moments (or really early on), it's because you got a totally shit hand (and didn't have the cards to fix it).
They will probably have to revamp it entirely, since it's basically collect-cards-to-win (or pay-to-win, if they include micro-transactions). Also one of the factions is complete ass (non-humans) and another (monster) doesn't keep up with the remaining two; in a PvP situation you'd be an idiot not to play one of the two human factions (and the whole game seems to revolve around spies (to a very repetitive extent) once you get access to a bunch of them). I thought it ran out of juice as a PvE game, as a PvP game it would be need to be completely different to compare to Magic or even Hearthstone.
It reminds me of people were excited about a mod that replaces all combat with Gwent. Sounds like that would be insanely slow and repetitive and run the game into the ground even faster. Again, makes me think the exaggerated positive response is a meme.