Since coming back, Oro has stated at least a couple times that the war doesn't really matter to him. He at least says that he really is only interested in what happens to Sasuke.
However, I think that Orochimaru is just trying to act like he doesn't care. There are times when he seems to indicate otherwise. His actions have been pretty important, at least when it comes to the battle against Madara and Obito. He brought back the previous Hokage (and is letting them fight instead of just releasing the jutsu) and helped revive the Kage. You have to remember that while Oro is definitely twisted, nobody in the Narutoverse is truly "evil". This holds true even for Orochimaru.
Just to leave you with something to think about. Maybe Orochimaru was acting on behalf of the Leaf Village this entire time too. We know that he was a member of Danzo's Root, and at one point served as his personal guard. Perhaps Danzo ordered Orochimaru to infiltrate the Akatsuki. Not necessarily to protect the Leaf Village, but rather to protect Danzo's interests. Given Danxo's relationship with the Akatsuki, Danzo's interest in Itachi and the Uchiha, Danzo's dislike of Sarutobi, and Danzo sending Sai to deliver information to Orochimaru, such a plot twist isn't too far-fetched.