Re: Orochimaru apparently is now on the good side aka the side sasuke and the 4 hokag
I was questioning this issue, too. We have to consider such issues so carefully. We can only come up with theories until Kishi reveals the truth about him. I have two reasons for his behaviour at the moment like yours.
First and foremost, he was talking with Sasuke-kun before they went to Konoha. There were flashbacks about why he wants to destroy Konoha, but we didn't see he was talking about them with Sasuke-kun. If be an optimistic person, I can say he has reasons like Sasuke-kun's. He maybe wasn't a pure evil afterall like we have been known. He may be after a vengeance. So, this avenger like character can make him at least a good person lies in him, but maybe it is pressured since this vengeance issue. And he is maybe really affected by Sasuke-kun's behaviour. We know because Sasuke-kun wasn't an evil guy from the very beginning. It was all vengeance issue that was manipulating them. Sasuke-kun's sincere behaviour can be affecting the person arise in Orachimaru-sama.
On the other hand, we can say there can be a different reason for him to join this war at the side of alliance with Sasuke-kun. I deeply afraid of Orochimaru-sama is going to initiate his plan when he joins the war. He is maybe waiting for to possess something more powerfull than Sasuke's body. I think he is maybe going to take over everthing and become the new sennin as So6P. Maybe he is planning to become jinchurikii of Juubi. There are a lot of fearful things coming to my mind to depress.
These two are all possibly until we see incoming mangas. I hope he is going to be a good person.