I'm not Kishi.... so before you reply "wait and see" I'm just saying. What are the possibilities that during the battle against Madara, Madara is too OP against Hashirama. Hashi was able to hold his own against EMS Madara but this Madara has the Rinnegan and the Juubi. I think Tobirama will be sealed and Hashirama will give his body to Sasuke giving Sasuke the Rinnegan. Naruto will be busy using the combined Bijuu powers against the Juubi. Is this even possible in the Narutoverse because Hashirama is edo tensei ? thoughts