I still think that the existing Kage system is going to be completely changed after the war.
Naruto's original goal was to be recognized by the village, which, as you pointed out, he already has achieved. He has other goals, though. One that he was Sakura's request to bring Sasuke back, and the other is to bring peace to the shinobi world. I'm pretty sure that the whole Sasuke thing is pretty much settled. They still need to face off and there's still some story there, but Sasuke is pretty much back. This leaves Naruto's only other goal.
Naruto is going to figure out how to bring peace the ninja world. The old village system isn't really going to allow this. Especially with arguably the most powerful characters residing in the Leaf Village. Naruto and Sasuke have both gone head to head with some of the Kage and (though Naruto has had better success) both have been able to walk away from their battles. I foresee some other government system coming out of the war that more resembles the Kage summit than the individual nations just going their separate ways after the war. This will usher in the world peace that the Sage Toad envisioned, and allow for multiple characters (Naruto, Sasuke, and Sakura to name some possible candidates) to jointly lead the shinobi world.
