http://www.vg247.com/2013/03/20/witcher-3-plot-extremely-ambitious-cd-projekt-discusses-narrative-depth/
Witcher 3 is extremely ambitious in terms of the number of characters and plots that we’re introducing,” Tomaszkiewicz continued, “but also in terms of how we want to present them. We want to tell a truly immersive and emotional story in an epic environment.
The overarching plot will have a huge impact on the state of world as a whole, but we’re not aiming at making Geralt savior of universe – this would be out of his character. As always, Geralt will get dragged into big events that he would otherwise stay out of, and influence them in his own way.
As for the ending states of the world, we are using the “butterfly effect” as we did in our previous games. So you can expect that seemingly unimportant choices may cause serious consequences later on in the game.
Nothing that new, just a reinforcement of the idea that the game will be better than skyrim and won't have a red, green, or blue ending.
I was thinking recently about why Witcher 2 is a great game. One reason I narrowed it down to is the fact that the game doesn't judge you. Just like in Deus Ex, your choices have consequences and you have to live with it, but the game doesn't give you a measurement of your morality. This is opposed to games like Mass Effect and Fallout 3/New Vegas which have the devs judge your behavior, applying their moral compass to decisions of ambiguous morality. At least in Dragon Age it was your companions who judged you.