Missing zone types... Maybe?

[MinosAmorino]

Every time you'll visit them, there will be no one else, so why would they develop more zones like this which are liked by noone?

There will be no one else because there's like 3-4 minutes of exploration in there, at the most, and then you're done.
Liked by no one? Jumping ahead of yourself, aren't you?
As for Outer la Noscea, they're a dead end and to small to even count.
Totorak is also a dungeon, not a zone. So you can't compare with that; even though I agree that dungeon is a bore.