GDC isn't a big press event like E3, with press/media being lumped in the "other" category along with Content Acquisition/Licensing, students, educators, and other job functions representing less than 15% of attendees.* So I wouldn't expect a new demo, as attendees would like to know more about the development process than the game itself. However, judging from past years and how long it's been since they've shown us anything, I don't think a new trailer is out of the question. Iwata will probably mention Zelda's 25th anniversary to go along with GDC's 25th and "modern gaming's" 25th, and might refer to SS when talking about "where we go from here," but I wouldn't expect anything huge (probably just WM+ stuff). Even so...will there be a live stream anywhere?Video Games Turn 25: A Historical Perspective and Vision for the Future
For a quarter of a century, the engine of video games has been "must have"—the viral communication of what a gamer simply can't do without. Sometimes it's hardware, sometimes software, sometimes an accessory, but "must have" always describes an experience that can't be missed—the next big thing.
Along the way, innovation has continuously reinvented the game experience in terms of graphics, player control and pure game design. But in the process, part of the magic of those early days of game creation has been lost.
As a leading player during all 25 years of the modern video gaming era, Nintendo has a unique perspective on what makes gamers grin, what defines the term "gamer" and what is essential to ensuring industry growth.
Nintendo President Satoru Iwata will draw from his development roots and talk not only about how video gaming has evolved, but also, more importantly, he will offer his views on where we go from here.
And here's an other reason we will most likely see a trailer, Twilight Princess got announced with a trailer at E3 2004 (two years before release) and then a new trailer at GDC 2005 and then a trailer at E3 2005 and so on, Skyward Sword got a trailer at E3 2010 (when it was almost finished) and now it's in it's last stages of development and will release this year so that's an even better reason to expect (but don't get mad at me if they do not show anything even though we 99.9% we will see a trailer)