I used to think Kakashi and Gai could defeat Orochimaru, in a very close fight, thanks to working together. Might be a little too hard for them now, but they have more support than that. Sasuke can hold off Itachi for a long time ? we're seeing him do that right now. So if those two do fight a one-on-one, that's Orochimaru against Kakashi, Gai, Asuma and Naruto. You really can't just hand wave the first three and then imagine Naruto has not moved a step before Orochimaru moves onto him.Orochimaru can likely take Kakashi, Gai, and Asuma easily. He just needs to hold back Naruto till Itachi kills Sasuke. And since he's bloodlusted, it won't take long. From there on, rape.
Sasuke is powerless against Susasano (sp?)
When Itachi is really going for the kill, Sasuke is unable to stop. Itachi halted Ameratsu to preserve Sasuke's body. He did not use Tsukiyomi to its fullest extent.
What if Oro fought Sasuke while Itachi occupied the Jounin? I don't see ANY of them surviving Ameratsu; MAYBE Kakashi.
And Susanno is unbeatable from what I can see.