Gaming site Faceoff Games has an interview with The Witcher 2 senior producer Tomek Gop. Here's an excerpt:

F.O.G: You've said that the this game's main plot will be shorter than the original Witcher, but that side content will be much more involved. Can you give us an example of how these side missions will play out?
TG: It's pretty much all about binding the quests with the story. The main plot of the game features the king slayers, so most of the things the player will do throughout the game will involve Geralt trying dig deeper into this thread. Even with things that seem distant in storyline (like for example, killing a huge monster that endangers the town), it still appears that there are strings attached. I don't want to spoil it.
F.O.G: We've been told there will be no "FedEx missions", that missions wouldn't have the player going from point A to point B delivering packages. Is this really true? Other games in the past have claimed the same, and have failed to delivery. Can players really expect anything different from the Witcher 2?
TG: I guess you're gonna have to wait and see for yourself. I've seen quests implemented and have already played them - it really works. Second thing is, we've got a fully open world right now, so you can explore all parts of locations from the very beginning, so many quests are presented to you at an early stage.

You can read the rest of the interview here.