As expected, CDPR's next project is indeed The Witcher 3, now revealed to be subtitled "Wild Hunt".
Summary from NeoGAF member that has the digital edition of the GI issue in question:
Originally Posted by INDIGO_CYCLOPS @ NeoGAF
World supposedly 20% bigger than Skyrim's
30-40 minutes to cross world on Horseback
New streaming technology (CDRED Engine 3)
Geralt's Memory is restored
Dude is f***ing DONE fighting for everyone else
Everything from solving MYSTERIES to slaying monsters
Coming out on "all top-of-the-line" consoles - I'd say that confirms next-gen is in.
More details inbound soon...