First, i would broaden the story much more and wouldn´t make naruto and sasuke the only focus, i would have done a part 3 to the manga and would have gone much deeper into the story and some things like death, creation, honestly, kishi can make a much bigger and better story, so6p could create form out of nothingness, he could give naruto a new goal such as contribute something great to the world and do something unheard of like so6p.
Before so6p, i assume ninjas were simply people fighting and assasinating, then he came along and introduced chakra to them, so before ninjutsu was really just them using taijutsu, but now u can do all sorts of crazy things with chakra and that´s what ninjutsu has become, the so6p is the one who introduced modern ninjutsu
Oro wants the truth behind existance and learn all jutsus, he could make Kabuto the final villian and u get the point.
What i´m trying so say is that there are so many things u could do with a story like naruto, so many doors u can go through, untill, he answers all mystery it shouldn´t end.
It should be a happy ending, that´s all