What really innovates this game is the non-linear puzzle solving and exploration. Every Zelda game before it always had puzzles that explicitly relied upon a specific item you got in the dungeon (bow & arrow, hookshoot, bombs, etc). Those same items would largely define where you could and could not go. With exception to needing the paraglider to get off the plateau, in Breath of the Wild you can use really any item or process you want to traverse the world and the dungeons.

Final Fantasy XV won't pull it off, nor does it need to because it isn't an open world game.

It looks open world because of its expansive landscapes, but the game won't be much different from the more "open" Final Fantasy titles of yore (as in not a straight line like FF X and XIII). The developers stated that the world won't be fully open to you from the get go, and will follow what's been standard progression for the series in titles like FF VI for example. In which the world would open the more you advance through the story or when you get access to airships and the likes later in the game. 

There's very limited pool of open-world action-RPGs out there that Nintendo can really get their (let's call it) inspiration from, and even the best ones (generally Euro-RPGs) have their share of problems...honestly, that specific genre is probably one of the genres with most potential to grow, and probably as equal potential to fail to ever reach any substantial improvement over already established "kings" (that are currently 10-15 years old).

As for Zelda itself, I'm still waiting to see more, so far shown open-world part is not too exciting for me, shrines (for my personal taste) don't seem as a good substitute for usual RPG caves and "climb everywhere" mechanic, while initially interesting, seems OP for action-adventure (would be perfectly fine in RPG with required skills for climbing).

I am aware of that, but because it doesn't change my concern I didnt bother with it. Open world or big expansive landscapes: Japanese games have never been good at these, because they dont understand the type detail that needs to go into them to keep them entertaining. Most players of MGSV said why couldnt the game just be composed of multiple mission areas with side ops as optional task during them? There was really no need for open world in MGSV. They did nothing with all that vastness and that is the primary problem when Japanese developers attempt to emulate open world. 

That's one example. Care to provide some more? Doesn't seem fair to dismiss all the japanese developers for just one game that didn't please you...

I remember a game series called Shenmue. It basically started/revolutionized the modern era of open-world games, and there were quite a bit of stuff you could do in it... 

Except for this one, I don't recall many games from Japan that aimed for sandbox/open world gameplay. JRPGs are the closest that come to mind, and they have their own strength and weaknesses compared to western open-world games, but are still no aiming for the same kind of vibe and gameplay sensibilities/philosophies.

We have not seen dungeons yet.

You give one in return and ask for more.

We can look at Zelda's own history - Hyrule field in both OoT and Twilight Princess were uninteresting and empty. Dragon Quest 8 went with fully 3D rendered overworld. It was vast, absolutly nothing to do in it though, but for its time it was cool. I already mentioned MGSV. The first No More Heroes is another bad attempt.

 We have shenmue... which is not world open world in the same way todays open working games are. I cant think of one Japanese the used an open world environment that was towards detriment. 

Its absolutely fair to dismiss Japanese developers in their ability to make a good and engaging open world, wether because they dont do it or when they do try we have more cases of it been average to below than something great.  

How is it like Ultima?

Those games aren't open world. They're linear.

Okay. I will go through it again - The tag isnt point my concern.

Anytime a Japanese developer decides to make a game with expansive landscapes, wether they be openworld world genre like Fallout, GTA,MGXV ext OR just games with big areas like DQ8 or Zelda,FF155 they dont do a good job of making them interesting.