There's no day or night cycle in D:OS 2, so that's the first and biggest problem with trying to camp for the night.
Needing to eat food rarely adds much. The only recent game I can recall which had you eat food was Legend of Grimrock, which was set in a dungeon with limited food resources, and if you were hungry, you didn't regenerate health/energy over time and when resting. In a game where there isn't really limited food, that kind of mechanic wouldn't add much. EDIT: Whoops, I forgot, there is infinite food thanks to some respawning snails on floor 6. Snail slices - yum!
There's no fixed party in the game, you could have one of several origins (or even no origin) and several companions with different origins, so that's another little obstacle which would complicate adding campfire chats.
Implementing a day/night cycle should be easy (just make it a bit darker ...not that I dislike a distant moon and stars :P ) and thinking more of that now, as I write, it should probably be added just as a nice "lifelike" feature, even without campfires. Also, in a game like this, and without day/night features, at least I presuppose, that they are sleeping some night hours, for example, at base without that now being graphically shown. So what I mean in this is that even without a cycle it could be a nice feature to camp out in the field or in a dungeon. Who says you will only camp at night when out and wandering through the countryside?
Adding some differentiated food and re spawning them in inns and the countryside (mushrooms...mmm) shouldn´t be that hard either. I admit I haven´t played through the first Original Sin and so far - agree that maps maybe not that big for a campfire feature - but then, at least, the travel to the Luculla mine over all those bridges were long enough for some well needed breaks a long the way.
The third thing you mention about chats I cannot understand since they are talking rather much already in Original Sin. Jahan for instance has talked for more than 15 minutes with my main character, only so far. Every companion does not need a background!
No, I still think this would be a great feature, even in this kind of game. As an alternative to using different beds for healing (in its simplest implementation) or even add some more animals, plants and so on to the maps which also will make it possible to expand the crafting part of the game! Instead of one pack of wolves there could be several, and re spawning mushrooms and plants - shouldn´t be that hard.
I want to sit by the fire singing a anthem, sounding like an imp.
