It will be the same Hyrule geographically, but you wouldn't be able to tell by looking. Or, at least, I hope that's what they do with it. I think BOTW2 will be set during a great renaissance. With Ganon gone, everyone's free to use the ancient Sheikah tech to its full advantage and create some marvelous inventions. We'll see the most advanced Hyrule ever. It will be a new golden age.
The trailer of BotW2 has promised at least a bit more land to explore, (possibly cave exploring and, if they listened to people's criticisms and ideas, then maybe a return of underwater exploration. That is only my hope though.) Aonuma has confirmed that the overworld map will be the same but that can mean both a lot and not so much. My father and I have put over 800 hours into the game individually as well (I KNOW we're not the only ones) and we have thoroughly explored the entirety of the overworld, but as there are no open caves (not including those beneath the castle as they were most likely hylian-made) and the only time Link goes under the water is when he jumps off into the water and is momentarily submerged. If they take advantage of the opportunity to imply underground and underwater exploration then that would open the door for a wider variety of enemies again, bringing back rats like from TP and WW, or if they want to have fun then they could create new enemies for both underground and underwater (both of which are entirely new environments)
I personally loved that there wasn't a whole lot of diversity in the monsters in BotW because it was such a great (re)opening game for old and new players alike. It was a great introduction for new players, helping them get used to what the LoZ series has to offer, while still giving old players a fantastic new game with waves of nostalgia and after nostalgia, (admittedly some flaws but every game has them). BotW2 has a great opportunity to expound upon that and add even more to it. Backlash in unavoidable, there will always be someone who'll be mad because one certain element wasn't implied or added, however, going solely off the trailor, it looks like the developers are adding new elements into the game by at least adding underground exploration, the rest is something we can only hope for.
I think SS is sort of Nintendo's soft way of making fans realize why they are going this direction so it will get more people who are on the fence about BOTW2 to join in. I just hope it doesn't back fire and they throw the baby out with the bath water dumbing the physics down again. I had lots of fun with stasis and the magnetism I pretty much forgot there was suppose to be a story most of the time.