Now that Duke is back, every company in the world will figure "it'll be done when it's done!" is a good enough excuse for years and years of waiting. I just wish we had somebody saying "we're putting it together, we have a new physics system, we have environment artists working around the clock, and in a couple months we'll announce a tentative due date" rather than "we'll get to it eventually, maybe, wait and see. By the way have you pre-ordered Portal 2 yet?"
I'm not convinced that they've even started work on it beyond a couple of concept sketches and a basic story overview... and likely not even that. I wish game companies were more honest about setbacks and what's going on behind the scenes, because by the time we hear about a new game it's just about finished and there's no way to inform developers if there was anything wrong with it.