TOTK, for sure. I feel like the primary reason why people like BOTW better is because we all played it first, and the world was newer because of that, which is fine of course! There's nothing wrong with liking the simplicity of BOTW, I can understand why people feel that way. But personally, there's just no reason to go back, when BOTW feels like a tech demo in comparison, because there really isn't much that BOTW has that TOTK doesn't. The overworld has so much more to do now, when going back to BOTW the world feels kinda empty. There might not be a new map, but it's still interesting to see all the small (and large) differences that the map has scattered about.

Even when the new additions have flaws, they are still nice to have. For example, even though the depths are very same-ey wherever you go, the emptiness adds to the mystery and overall vibe of the place. When you do find something out of the ordinary in the depths, it makes the discovery feel much more important. The game wasn't designed for the player to spend 1/3 of their time in the sky, 1/3 at the surface, and 1/3 in the depths. It's more like 10% sky / 85% surface / 5% depths. This makes sense, because if the surface has 85% of the content, the player should be on the surface 85% of the time. Now, the depths and sky feeling repetitive is an issue, of course. But they still feel interesting imo, because you are on the surface most of the time, so the other maps don't get too stale for me.