And the accompanying update finally fixes dialogue in co-op. Thank goodness.
Larian Studios has released the first free content update for Original Sin, and it basically has two parts: there's the two companions DLC, which adds Bairdotr the bow-toting ranger and Wolgraff the dagger-wielding rogue to the game. Both have their own storylines, and, unfortunately, both can only be recruited in a new game.
But for those who don't want to start over, there's improvements to be found on the bugfixing side of the update. Perhaps most importantly, in co-op, you can now properly listen in on conversations the other player is having, even if you're on the other side of the map. So there's no longer a need to re-read conversations in the journal, because you get to watch them live.
Apart from that, there are other improvements like better skill effects, fixes for missing sounds, and a lot of crash- and quest-related bugs have been eliminated as well. You can have a gander at the full list of changes here.
You can also take a closer look at the new companions (and the fixed co-op dialogue system!) in the video below: