They also said " All three areas seem gigantic, though I think Dragon Age: Inquisition is probably a larger game overall.""There are three or four major areas to explore, each of which is its own open world. However, these are discrete maps you travel between.
You can't, for instance, sail from Skellige to Novigrad. Instead, you go to the world map and "travel" to Novigrad. I asked why, and was told it's because CD Projekt wanted to keep the geography of the realm consistent while still representing all these areas. Basically, they know it would take hours of game-time to sail to Skellige, so instead you just fast-travel there." PCWorld, Witcher 3: Wild Hunt hands-on: Four hours with the most anticipated RPG of the year
I'm getting the feeling that W3 will not be as huge as I have imagined it to be if its comparable to DAI in the slightest. But I'm still hopeful.