That would be cool. But Orochimaru couldn't even take over Sasuke.
What if now that Madara is alive Orochimaru were to join him. He is much stronger than Sasuke and has the Rinnegan. That would put all the Edo Kages minus Hashirama against Naruto, Sasuke and the Shinobi Alliance. What do you think?
There is no real purpose on Orochimaru joining Madara.
Hasn't it already been confirmed that Hashi can't be controlled by Oro?
Either way I really hope this happens. The odds are so against Madara right now. Maybe Oro will just dispel the edo tensei to get Hashi out of there