Breath of the wild had two maps. The world, and the shrines.
Tears of the kingdom has four maps. The sky. The over world. Caves. And the depths. Not to mention the temples that replaced the four beasts are much larger than those beasts. They went back to OoT size temples.
The over world is very much different than it was in BotW. The number of quests is vastly more than in BotW.
Yeah you get heart containers again. Just like in every single Zelda game ever made.
The graphics, lighting, and especially the physics are improved a huge amount from BotW. (Although strangely the rain effect is worse). Like those are the things every game dev have been drooling over since it was released. And it runs at a smoother consistent frame rate than the previous game as well.
Sure you could argue BotW should have been TotK. You could also argue Super Mario Bros 3 should have been Super Mario World.