I have always felt that the Darksiders games built more of a personal story than overall end-of-the-road thing.
We know how it's going to end - some motherfuckers are gonna die - but I also think that all the upcoming story that can be revealed, without too much being spoiled, was done in the first game. DS2 added something in that it showed us who Death is, outside of being a baller. It also gave us some a detail as to how it's all going to end - with Humanity, and the Balance, being restored and everyone cleared of guilt.
Not much more to add to that, IMO. Just how each of the Riders was personally dealing with War's imprisonment, and what they're trying to do to help free him, and that's what I feel DS2 was.