The next console Zelda will come within switch's lifetime for sure. Aonuma said his team didn't take advantage of the Switch's power with the BOTW port and Miyamoto talked up the fact that they have these assets, engine, etc. so like Majora's Mask, I think we'll see something come out rather quick. So I'm going to say 2021 we'll see the next Zelda.

Even though Majora's Mask is the best Zelda game I've played, I don't really know if that will work for Breath of the Wild. If they make a game like Majora's Mask for Breath of the Wild, reusing Hyrule would be one of the worst things you can do. It would feel highly repetitive. On the other hand, you could make a smaller world like Termina that's unique on it's own, but if it's too small then the entire point of BOTW's engine (exploration) would be put to waist. I think the game would have to at least be 60% as big as BOTW, but I'm kind of worried Nintendo wouldn't risk doing that because it might get them marketing backlash for releasing a smaller side project for 60$. To me, side stories are the way to go but I just think it's way harder to do for BOTW than for Ocarina.

OP : I don't really want a 2d Zelda game and I don't think it will happen, but maybe it will. Who knows. I'm going to guess we get the next Zelda by 2019 or 2020

Thats's a fair point. I agree that trying to replicate (or even surpass) the success of BotW would be a mistake. It's a once in a generation type of game.

I think Aonuma et al. should reuse the assets and the engine and make a smaller-scale adventure in another region. Maybe even a large island, and make water travel more of a focus.

I agree that exploration is a big part of BotW's success, but even more important is the physics engine. If a sequel includes the same emergent gameplay and improvisational combat, I think it can survive with less real estate.

By 2020 there should be a new zelda.

Yeah I definitely agree. I think LoZ in general needs to get away from the Hyrule set up in general, so I think a side story like Majora's Mask would work very well. I wasn't trying to discredit your idea, I just think they need to approach it carefully.

2020

I'm also going with 2020.

Having a Majora's Mask type game, where they can reuse assets and engine, to Breath of the Wild would be perfect. They shouldn't even try to one-up BotW this gen, because it'll only disappoint. We need a totally different view, a companion game like Link's Awakening and Majora's Mask were to A Link to the Past and Ocarina of Time. I'm not seeing them do another smaller A Link Between Worlds type game anytime soon on modern, powerful hardware like the Switch. Hyrule Warriors/Crossbow Training-like spin-offs could happen sooner though. So could a remaster, but with only Skyward Sword remaining I hope they'll wait with that for at least this generation, on account of it not being that old yet.

There's 2 Zeruda teams now. The A Link Between Worlds team is probably ready to release their game in 2019, the next odd numbered year. The BotW AAA team prolly 2023 with a Nintendo platform launch.

Going by the few things he said I picture it more like a stealth game akin to Metal Gear Solid

Zelda is a bi-annual - sometimes annual if you count re-releases.

It's a bankable franchise that drives hardware - so you gotta believe Nintendo wants another one ASAP once BotW sales slow down.

If they simply reuse BotW's engine and accomplish something similar to Majora's Mask - I'm sure fans will immensely enjoy that. Not every Zelda game has to be a technical breakthrough (few Zelda games truly are tbh).

Don't underestimate Hyrule Warriors 2 or possibility of other Zelda spinoffs. What game studio wouldn't want to work with Zelda?