I really enjoyed playing D:OS, so now that I've completed the game, I'm looking for something really similar (with quests, interaction with environment, hidden mechanisms to open doors... and also turn-based, because I prefer to have time to think of a strategy).
I thought of Neverwinter 2, but I'm not really sure about the exploration part (like finding mechanisms).
If you know a game like D:OS, please answer me :)

I know this is an old post.

try Temple of Elemental Evil, you will need the Circle of Eight mod pack to make it work, one of my favorite games of all time.

Wasteland 2, is really good

Arcanum, pretty good but dated

i have heard good things about Shadowrun: Dragonfall

a sequel to Planescape: Torment is in the works and should be out 3rd qtr 2016