What Are You Playing?

[Nintex]

Depths were definitely a missed opportunity. Just big empty spaces.

I wanted actual underground cave systems and interlinked dungeons.

They went halfway and stopped.

I think they just ran into technical limitations.

As far as I understand the plan was to do more DLC for BOTW (hence using the same world and the early the announcement trailer) and that turned into a full fledged sequel instead that they kept adding things to as they kept working on it. They cut a bunch of Sky Islands because the sky got too busy.

What I find odd is that it has the depths but also the caves and some of the caves are nearly dungeon level.  

The game doesn't explain it very well but in hindsight there's an obvious linear order to tackle things.

Quest 1
- 4 main sages (Wind, Fire, Water, Desert) / Land + Sky

Spoiler:  (click to show)(click to hide)

- Stable rumors / Land

Quest 2
- Maps towers / Land

Spoiler:  (click to show)(click to hide)

- Geoglyphs / Land + Sky
- Restoring the mother statue / Land + Sky

Quest 3

Spoiler:  (click to show)(click to hide)

- Finding the Master Sword (Korok Forest) / Land + Sky + Depths (first time depths are necessary to progress apart from the Goron temple)
- Hyrule Castle / Land

Quest 4

Spoiler:  (click to show)(click to hide)

- 5th sage (Spirit) / Land + Sky + Depths (depths take a more prominent role)

Quest 5

Spoiler:  (click to show)(click to hide)

- Finding Ganon (Yiga Clan quest) / Land + Depths

Quest 6
- Final battle

If you play the game in this order than the final battle is basically the ending of a long quest through the depths.
I did read that if you don't unlock the Sages, you actually have to fight all the bosses again.