Not out yet and it's disputable, but Dragon Age: Inquisition (out 21 November in the UK) may fit the bill. There are discrete locations, so you can't wander everywhere, however, the locations are reportedly massive (it's been said many times that a particular one, not the largest) is bigger than the whole of Dragon Age: Origins, and there's been a drive to make exploring a large part of the game.
Pre-release, so that may prove an exaggeration, but I've pre-ordered and will complain, or not, about how well it fits the hype.
Edited extra bit: not played either, but I believe Two Worlds II and Kingdoms of Amalur are both open world fantasy RPGs.