Personally (no offence) I don't think that will be the case at all. I think Sasuke will kill Oroichimaru and then go hunting for Itachi while killing Akatsuki on the way. Naruto on the other hand, will be looking for Sasuke or hunting Akatsuki with other konoha ninjas.

Also, I have a strange feeling that there is one other sharingan user other than Sasuke, Itachi and Kakashi who can use the mangekyou sharingan (possibly Uchiha Madara; link from the Nine-tails on the first ep of shipuudden). Itachi wanted sasuke to kill naruto to get the mangekyou sharingan but really, it makes no sense him wanting sasuke alive; if itachi wanted, he would have taken sasuke out a while ago (Itachi wants Sasuke's sharingan for some reason, whether it be to posses him, use them to unlock some hidden power in the uchiha clan or whether he wants to take Sasuke's sharingans for his, possibly improve his own).

The reason I said Madara must be alive is because they mentioned him with the nine-tails and nothing really does go without an explanation, plus, how did Itachi kill the WHOLE of the konoha police alone? It would be a ridiculous fluke, he was good but not THAT good. Madara must have helped him. Also, he must have been taught by someone to use the sharingan to its fullest and that would have been Madara, the starter of the Uchihas. Madara's location would either be in Akatsuki or something related to it where Itachi can get help from. I'm suggesting out of the members that we know at the moment, Madara is probably Tobi as we can not see his face, there is a possibility him being the main leader thing too but that persons eyes do not look like a sharingan. If he's not in Akatsuki, he either leading it or hiding in a village waiting to reveal his full "plan".