Killer Bee is always fun to see on screen because of his personality and fighting skills, I'd definitely love to see more of him. In Kakashi's case, given his power and influence I would be kind of surprised to see him not have any role in Blue Vortex at all, especially given what happened to Naruto; maybe he'll get involved in some way later on, who knows. I think the main reason we don't have a lot of scenes for post war Kakashi is because they didn't animate his Retsuden novel, which is a shame, because he does a lot of cool things as Hokage. Hopefully they'll animate that soon. Orochimaru I don't really care about as much, but given how influential he is in the Naruto world, I wouldn't be surprised if he makes an appearance at some point. I would like to see how much his prowess with Wood Style has grown though, since he did gain it during the war and knowing Orochimaru, there's no way he hasn't been training with it and testing his limits,