The new cavern reminds me of the one we already had before. I think it is intended to be a time sink until the next dungeon. I mean we ate up the island content and the vault so fast that they had to put something in to slow us down.
Korthia had content. You might not have liked the content, but it still had lots to do there.
I could spend a few hours there each day. And i did
Zaralek caverns does not have content. I have got so fed up of waiting around for anything to happen that i have stopped going there other than my weekly quest which is done under an hour.
I didn’t mind korthia or Shadowlands really. I prefer everything about Shadowlands over Dragonflight. Not that it makes it good or anything but I had way more to entertain me in Shadowlands.