In 2016, 3D Zelda is making it's first ever leap into actual open world design. Previous Zelda games (and not just the 3D ones) have often taken notes from more open games, such as having huge overworlds or player choice progression, but Zelda for Wii U is going straight into the open world genre, as it appears. Nothing so far can tell us how exactly the game is going to play and work with open world elements, so pondering over whether 3D Zelda will remain in this style for entries to come is debatedly pointless right now. For now though, let's imagine Zelda U is an amazing open world game, basically perfect. 98 Metascore. Do you think 3D Zelda is going to be open world from then on?

Let's take a look at a comparable, relevant game: MGSV: The Phantom Pain. This game is pretty much the first ever Metal Gear game to be open world. Like Zelda, it used a lot of open gameplay concepts in previous installments, but was never aquainted with a huge world to traverse. Now MGSV is critically acclaimed for still having player choice be a big factor in gameplay, while mixing an actual open world. It may just be the perfect example of how open a game can be. However, many detractors have criticised the game for having a subpar, horribly paced plot, something that may be due to how focused the game was on gameplay (among other things). In a world where Kojima were still making MG games, I think he would go back to making the shorter, more story focused installments. The MGS series was a rare breed, where it could be easily stated that gameplay and plot were equally important. The story was what the games were known for!

For Zelda, the story ain't that important when compared to gameplay. But the thing that makes me think that it's not going back is the simple observation that Zelda has had the basics for what an open world game could be for nearly 17 years. Here, it's just making the game bigger and putting in less loading screens. The core isn't changing. And yes, traditional 3D Zelda and open world 3D Zelda are still going to be quite different in how the experience is, well, experienced. But only time will tell what effects Zelda U will have on the series.

EDIT: I guess I have to clarify. What I mean by open world involves using the open world itself for a less linear game, like actual open world games. The previous Zelda games are still extremely limited in terms of progression. As well, the overworld had always felt more like a place to get you to other important places, the world was never quite streamlined so that it blended towns and the like with the overworld, making it feel more alive. And Zelda 1 and other 2Ds were a precursor to what an open world game could have been like, they aren't exactly open world in a modern sense.

Zelda has always been open world...

first zelda game was the first true open world game

Isn't it already an open world game?

I'd consider Windwaker to be the first 3D Zelda with a seamless open world. OoT, MM, and TP all had seamed open-worlds (if one considers The Witcher 3, with its loading screens between hub-worlds, to be open-world then so should they consider the 3D Zelda's which only had loading screen between buildings and dungeons.)

For one, it already was open world. To answer the question: Of course it will go back. We went from an open world Wind Waker to a more structured open world Twilight Princess to the incredibly linear Skyward Sword. Sprinkled in between was the ultra linear mission-based Four Swords Adventures. That's just how Zelda works; they always flip flop on these basic concepts to change the pace up.

Almost every Zelda game was open world.

There are a lot of kinds of Zelda games: the 2D open world that the NES ones were at the time, the more structured 2D worlds from ALTTP, ALBW and the GameBoy and GBA games, the first 3D limitd open world of the 64 twins, the full 3D open world like WindWaker, more structured ones like TP and SS... They don't get attached to one style, at least in that regard. And having into account how expensive and difficult to make an open world Zelda must be, they won't want that.

Just played Wind Waker HD and it was quite open world IMO. It had side messions and optional stuff you could do. Linear main story progression doesn't mean the game isn't open world. Elder Scrolls games have linear main story progression.

And after Wind Waker you had Twilight Princess and Skyward Sword. So sure, it could go back.

I think open-world is more generally used to mean seamlessly explorable world. So that nearly anything you can see, you can go to without the loading of different areas.