In an interview with Nintendo Power, Miyamoto talked a bit about the new Wii Zelda, and made the statement “I don’t think it’s going to be that radically different.”
This could be interpreted in many ways. Most likely it’s just a reassurance that we aren’t going to see “Zelda in Space” or “Link fighting in WWII”, or one of the other many wild theories that always appear during the speculation of a new game.
However, there’s also a chance that he could be referring to the style of gameplay, or the graphics, or any number of things. I guess we’ll just have to wait until there is more actual information on the game before we know for sure.