Why would Hiruzen fight against Oro? :|
I doubt its going to be that organized. There's only one way to stop Obito now, and that's what Kishi will show us.
Hopefully i'm wrong because i won't to see the Hokages in action, especially Hiruzen and Tobirama (also Minato, i want to see something new and that can be considered heavy artillery ).
There are currently too heroes and only two villians. I think the eye of the moon plan will suceed. The villains will be winning as they always are before the cilmax. Then Naruto, Sasuke, and Bee will fight Madara and Obito and win against all odds.