There's a few reasons why the Metal Gear Solid: Snake Eater 3D trailer has increased our interested in the title.
Maybe its the ability to kit out Snake's camouflage suit in whatever you take snapshots of with your camera. Maybe its the use of the gyro-sensor when crossing bridges.
Or maybe its seeing Nintendo's long-tongued green dinosaur make a special appearance (with matching SFX) in the title. See Yoshi in this E3 trailer right now, along with a collage of screens for the title.