Not all Zelda games have had instruments, or major ones. Most of them have had some degree of control over music, though. Though most games don't have something as interactive as the Ocarina, Wind Waker, or Harp, or, that is, something you actually play. In many of the old games, music instruments served a simple purpose and could be utilized with a push of a button.
It wouldn't be radical of Nintendo to do it, because it would by no means be a first, but I'm hoping that they continue to make fun, interactive instruments for games (at least the three-dimensional ones) because I love instruments in Zelda, how they sound, the ability to play music, and how they affect the game. I think they're a great contribution, and I hope we continue to see them.