The Akatsuki seem really strict about not killing a jinchuriki. I think this may mean that if a biju dies, their plan is ruined, so here's my theory:
I think eventually Naruto will become Hokage, but has to destroy the Kyubi and the only way he can do this is by killing himself. This means Naruto has a great battle with the Kyubi so that he can gain proper control over his body and stop the Kyubi healing him. He will also have been Hokage for only a short time and then Tsunade will have to reclaim the title (like father like son). Sasuke will then realise how important Naruto's friendship was to him and that all Naruto's arguments about why he should come back to the village actually made sense.
-Naruto earns his reputation as a hero his dream to be Hokage
-The Kyubi is defeated
-Naruto finally fulfils his promise to Sakura in bringing Sasuke back (not quite how he pictured it - but still)
-(Sasuke kills Itachi at some point before this)
-Everyone is happy (apart from all the people who grieve over Naruto's death: especially Gaara and Hinata)