So, oro is back... many of us believed he would return.
I'm thinking Oro will help aid tsunade and the other kage's in the fight against madara while sasuke unites with naruto and sakura and the others in the fight against tobi. Oro does know the secrets of edo-tensei.. maybe he knows everything about it - more than madara.
While oro helps seal madara, sasuke gets all his information from tobi.
What you say boys?