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They've shown very little gameplay, so I don't think we should take the trailers as indication.
The way I see it is like this:
From what we've heard of Breath of the Wild's development, I really get the feeling that most of the game's development was dedicated to really getting the foundation right, the engine, mechanics, physics and all that. When Aonuma came out in that video saying they had to delay the game because they just started having fun with it and started coming up with loads of ideas, to me it seems like that's when they really started to figure out the story and develop the shrines, Koroks, divine beasts, enemy bases and weapons and just about everything you do. So of the 5 and a half years between Skyward Sword and it, probably only 3 years or so were dedicated to actually filling out the world with stuff to do.
The gap now to Tears of the Kingdom is over 6 years, and to be fair some of that time probably wasn't spent in active development, but from everything we've seen, it's clear that it's using the same engine and reusing a lot of the basic mechanics and physics, as well as reusing the original overworld. So that's 6 whole years where all they did is fill the world with new content.
I hope they realize we need more variety of interesting things to find. Breath of the Wild starts feeling small when you realize that the suspicious looking thing in the horizon is just gonna be another Korok. Ideally we'd be able to find all sorts of different things, Koroks and shrines can stay, but it'd be awesome to be able to come across more different enemy and boss encounters, mini-dungeons, who knows. But whatever they do, I think the content is going to be a lot more interesting and lot more, than Breath of the Wild. It seems inevitable really.
