Well.
Our 4-player game is now over.
My friend came yesterday and took back its TV.
During that whole 27 hours-and-then-abandoned game, I was thinking : Wow, if only I knew it would be like this, I would have recommended playing the first opus, but then again the first one wasn't really enjoyable with 4 people even with the mod.
I think I'll restart a game with only one friend because we waited a while for this one (and well, I payed for it, and some part are still kind of enjoyable), but I must admit the game is a disappointment.
Apart from the bugs, you can add "no clue on making an acceptable UI for a controller for the second opus". No thought was put in it, it was pure genius in the first opus and needed some tweaking (we still can turn on/off the headgear : Come on Larian, it's just a button to put somewhere, you had two years to do it!), ability to teleport from the map for example, no autofilling the action bar (this one is so stupid, I really don't get at any point someone thinking this could be a good idea, but this is again a proof the game was never thoroughly played on controller). The simple fact that you can't do everything you can do with K/M with a controller is just bad design.
So yeah. I did understand the critics on the first one saying it was great, I really cannot grasp the rage now.