Regarding, long-awaited confrontations, Kakashi running into Sasuke seems to make the most sense since they havent seen eachother after Sasuke left the village. I am actually excited at the possibility of them having a dialogue because if anyone was ever able to get through to Sasuke, or at least get him to listen, it was Kakashi.

Naruto, Yamato, and Hinata running into Deidara and Tobi would be cool too. I think Yamato's earth/water elements would match up well against Deidara's clay and Hinata's Byakugan might gives us more info about Tobi.