I've been into the underdark twice, both in patch 9 and never seen kua-toa, the Shar statue and wizard robe (I found the trap bridge but getting past it was so tedious I gave up, that's on me I'll admit), the lava elemental or been able to make heads or tails of the arcane tower. I thought I'd explored it thoroughly when I went there and there was nothing all that interesting about it.
My feeling about the game as a whole (and I've said this before) is that I feel as if Larian just expects us to explore because 'that's what you do' while the story itself incentivizes finding a particular path and hurrying down it unless you're playing a particular sort of character.
