That's a pretty interesting observation. It will be interesting to see how much freedom there is in this Zelda game. As you said, it probably will not be as open as the Witcher, where the world doesn't hang in the balance. Where as in a zelda game, you are the one to stop the forces of evil from bring about etc etc. The character building is also pretty important, as you said, different allocation of skills or resources will lead to different play styles. Zelda games to my knowledge, focuses more on items that help you progress to a new area or perform new actions to help you advance so the pacing for people mayeb be different but the path will be fairly similar. I'm also a big fan of the freedom and Zelda not being considered I guess, a typical "RPG", I wonder if it will be more focused as you said.

I feel like there is still so much we don't know much about BoW but going into it with a bit of mistery might work in its favor.

While The Witcher 3 is my current GOTG, I agree that the combat felt a bit tedious at times because of how repetitive it can get. But there were so many other aspects it did well. When taken as a whole, the positive far outweigh the negative. The writing and side quests were all very well fleshed out and kept things interesting. 

That being said, The Witcher 3 simply doesn't have the gameplay diversity for which the Zelda franchise is known for. That is mostly due to the fact that Zelda relies on an inventory of items and weapons to spice things up the more you progress, and each of those items opens up new gameplay possibilities and features. While The Witcher 3 relies on the same gameplay aspects throughout its entirety, combat, horse riding, Gwent, exploration and detective work. Zelda has almost all of those, but with the varied inventory, I expect BOTW to be much more enjoyable to explore, even if its world ends up being much smaller.

So from a gameplay perspective, Zelda will more than likely be much more fun than The Witcher 3. But I think it won't have the edge when it comes to story and writing. Nintendo will offer a much more fleshed out story, much more emotional than what the series is known for, but I doubt it will reach the maturity and depth that's found in The Witcher 3.

Overall though, I think I will enjoy Breath of the Wild more than The Witcher 3, simply because it will be much more fun to play through multiple times. I did almost everything that's possible in The Witcher 3, and after that, I went into New Game + and I simply can't play more than an hour at a time because of how repetitive it gets once you know everything the game has to offer.

I fully expect Breath of the Wild to take the GOTG crown from The Witcher 3.

Someday in the right mindset I will play it again to enjoy at least the story and the beautiful localizations, it made me very interested about the polish books but I was honestly expecting Witcher 3 to be way more like a european mature dark Zelda, which sounds beyond cool, but the gameplay is nothing like Zelda really, I wanted a more dynamic and lighter approach to the genre, one that puts more weight in the fun aspect of an open world, something with fun combat that lets you interact with the world more with the gameplay itself than with dialogues as well written as they can be, but Witcher 3 just wasnt that, also for an open world I found exploration less fun than in the otherwise inferior Fallout 4, it was just very addictive to look around the world on that one as flawed as it is, and at the end I spent more time on that one even knowing that it was not even in the same league in many aspects, so yeah good game but is maybe just not for me, I think Zelda will be a more joyfull experience and the breath of fresh air that I was hopping for the open world "genre".

I think it will become this generation's Breath of the Wild

When you think of the Zelda series and ask yourself which game is the best one most times you answer yourself with Ocarina but the more you think about it, the more you put most games on the same level, you can't just pick one, they offer such diverse experiences that all of them are the best one at something, now with BotW I feel that this could change, I think Ocarina will remain the most acclaimed but BotW will be THE ONE that stands out, above all other games in the series.

I'm among the odd ones, but OoT has never ever once been the answer to that question for me.

A Link to the Past and Wind Waker are both much better games in my book. But the premise/story of OoT is probably the best in the series so far.

Nothing is really new abt BoTW, but it surely looks beautiful

Definitely be up there. I cant say if it will top Mario Galaxies, in fact i dont believe any game can. Top 15 is looking likely though.

Think? by that new trailer is already a given that it will be.

I'm not too sure, but I think it might become my favorite Zelda game! It remains to be seen.