After playing the game I thought that there is somuch potintal. Inlcuding with the DLC. There are two directions they can go.

First is a Sim/RTS stlye rebuild of Hyrule. Including the creation of more towns and rebuilding the ruins. While at the same time defending from enemies. Including a new enemy invading from the sea. The more towns you bulid the more resources you have but also the more people you have to defend. So town placement is important. There could be more indept stories about ruins such as the lost city and the mazes.

Second is a BOTW 2 that expands north west and northwest increasing the map size by 4 times. With the story interacting with the present map.

I would rather see this than  bunch of DLC. But the possibilities in this game are many.

How about a "real dungeon texture pack" for 1.99$ that will give the divine beasts actually diverse texture designs, you know, like as if the designers gave a shit   : p

In all seriousness eh. I feel like all these ideas are coming from the perspective of consumers who think bigger is always better, but I just don't see it. A horde mode is not what Breath of the Wild needs, I'll admit it could be interesting but considering how bad Fallout 4 pulled it off .... eh. It kind of ruins the uniqueness of Breath of the Wild's empty space. 

I don't want a map that's 4 times bigger. I want them to make a new game in a new original setting with more density than quantity. I love Breath of the Wild's world but even then I had to give the game some liberties, it just felt too unfocused on occasion. 

4 times the size? Lol and and RTS on a console? Wow!

Pikmin?

Really the only thing they could do after Breath of the Wild, world-wise, is just make the overworld a globe.

Just give me anything new and substantial. I'd prefer darker themes.

I do have a ton of ideas for a second game using that engine though.

Or twice the size using the existing world heavily. Basically expanding on the current story with the same engine.

Some RST elements alone with the sim part. Again, you will be trying to rebuild Hyrule while defending it

Hopefully they'll re-use a lot of assets to make it much easier to do so.

If I were to add anything, it would be a new medium sized area with a few small villages with lots of quests and dungeons.
In the main game I often felt I was just looking for shrines or Korok seeds, and some missions felt unconsequential.

I don't see how including Fallout 4's base building or quadrupling the map size would benefit the game, since the former wouldn't fit and the latter would be a diluted version of the same (ot take 15 years).
On that note I propose they add karaoke from Yakuza and the chopper from MGSV

This. I already felt that the overworld was too big as is, it desperately needed some caves and full-sized dungeons in there. I hope that for the next game they put more meaningful content in the map instead of putting stuff like 900 Korok seeds that most people won't even bother with. Also cut the shrines count to 70-80 at most and make them bigger. Quality before quantity, as you've said.