This game takes my favorite open world in a video game and adds so much more to do in it through the addition of caves, more involved sidequests, and a greater number of shrines.
Elements such as dungeons are significantly improved as well, with more diverse theming and more organically integrated puzzles that often make decent use of the dungeon as a space.
Link's abilities in this game are fantastic too. The Ultrahand allows for a lot of creativity, Fuse makes the weapon system feel more customizable, and Ascend allows for clever use of vertical space. (Recall is cool too, but it's more puzzle focused than the rest.)
If I had one major criticism with TotK's new concepts, I would say that the Depths don't live up to their full potential. They're a bit lacking in variety, and there isn't too much to do there aside from fighting enemies and gathering resources to help you on the surface. They're a cool concept with some good atmosphere, and if you enjoy exploration (which I do), it's nice to have more of the world to see, but it certainly isn't as exciting of a place as the surface.
While I do think Tears of the Kingdom is generally a clear improvement over Breath of the Wild, there are a couple areas that feel a bit purposeless in TotK compared to its predecessor. In combination with the difference in abilities, this leaves both games feeling distinct despite TotK having more content and better core gameplay.
Make no mistake though, this game is one of the best I've played due to its wonderful world, engaging core mechanics, and solid puzzle design.