We may not have a clear idea of what the future holds for the Witcher series, but here's something to tide you over: an isometric, open world, stealth-centric RPG from sometime Witcher 3 senior quest designer Jakub Rokosz and his new team, Fool's Theory. We've known about Seven: The Days Long Gone for quite a while now, but all of a sudden it's due for release in December.
Seven is a post-apocalypse-themed game, and seems to have opted for a collision between Falloutish sci-fi and traditional fantasy RPG magic. It tells the tale of master thief Teriel's journey across the sandbox prison island of Peh, making what sound like Witchery decisions about whether to help or abuse its citizens as he does. Though he's a stealth sort of fellow, apparently he's fairly handy in a straight fight too.
Here's a vid introducing its world...
...and a minty-fresh one showing the kinds of ways you can move around it:
Another one of the CD Project alumni working on Seven is Witcher 3 composer Marcin Przybyłowicz, incidentally.