In an interview with ONM, Shigeru Miyamoto stated The Legend of Zelda: Ocarina of Time 3D and StarFox 64 3D will have newer features other than beautiful 3D graphics.
“Of course if all we were going to do was to port them over to 3DS we’d have a load of old games with 3D visuals. So we’re talking to the teams and coming up with ways of adding new ideas to the games.”
He also went on to say that the old games could be easier to play in 3D. “When you’re playing a game in a full rendered world it can be very difficult to judge the distance. With jumping up at question blocks in a Mario game, for example, 3D makes the game easier to play, while we are also coming up with new ideas too.
“The other thing that’s very important is that because it’s the same system for everybody, developers don’t have to worry about who has which TV and things like that.”
What new features will there be? Sword fighting on horseback? More dungeons? Who knows?