Summing things up: Larian want to make Beyond Divinity "right". Understandable,but not exactly what I was looking for. Oh man, first Dragon Commander, now this... it seems like I'm not really going to play any Larian games within 5 years until Divinity 3 release.

Raze
That's why I said "deus ex". If the story is not related to original plot - it is not a prequel, it is spin-off. If it related to the original story with the Damned One - we know it very good enough, there isn't so much left to put on the field, so what kind of possible Original Sin it could be, if not about the Sword of Lies and Damned One? It seems like they are coming up with something totally new thus "deus ex machina"element. I find them quite cheap, especially when it comes to universe/setting consistence, but that's just me, may be (too much Martin and Bekker).