Well, after Naruto absorbs all the Hokages, the story could take a turn where he has to deal with the internal politics of the village. The other ninja might be jealous or afraid of his new - found power. He'd have to find a way to balance his new abilities with the trust of his comrades. Also, he might be drawn to explore the secrets of the ninja world that the Hokages knew, which could lead to all sorts of adventures.
The story might progress with Naruto becoming a sort of super - ninja. He could start by using his new powers to protect the village from threats that were previously too difficult to handle. Maybe he'd face off against an ancient evil that only his combined powers could defeat.