Interesting thread idea, although maybe a bit too soon. I'm not interested in speculating on this myself. From what I've heard - you can kill everyone and still finish the main quest - there isn't going to be a very deep main story.
You could kill everyone in Divine Divinity and it still had a deep story-line. You could do the same in games like Baldur's Gate, Arx Fatalis and (more recently) Dark Souls which all had intricate plots.
I know Macbeth corrected these doubts but I just wanted to add that not every game with all (or most) main quest NPC's being killable have small plots.
@Elrodeus
I actually thought Divine Divinity had a rather good plot. I mean it's not Planescape but it doesn't have to be or even have to have as many words of dialogue. The backstory (prologue) sets up all the events and I recall it covers at least 18 pages in the PDF it's in and then the actual story in game is of rather good quality with many events happening as the story progresses. I'd compared it to Baldur's Gate and I'd have to say the story is actually better.
@OP
The gods are dead? Where did you hear that? The Divine One receives his power from the seven gods in Divine Divinity so clearly they aren't dead. It's also likely that The Patriarch is a god considering he has the powers to create and apparently knows of the goings on across the universe.
Also Adam and Eve's sin wasn't of "learning" but of giving in to temptation and thus being disobedient. Hence why the apple is now associated with tempting. In any case just because this Divinity has the subtitle of "Original Sin" doesn't mean it'll have any inspiration from this. I personally think Original Sin in this instance is referring to the what ticked everything off leading to the events of Divine Divinity with The Divine One, thus to Damien and then to The Dragon Knight.
