I'm sorry but as much happens between Naruto and Sasuke, whatever happens to their characters- Naruto VS Sasuke is what we've always been waiting for and will have loads of emotional tension no matter what happens. Thing is though, can we even be 100% certain that fight will happen> There is absolutely no way to predict where Kishi is going with this stories finale.
There are like 1000 different combinations. My personal favourite is Orochimaru taking control of all 4 Hokage at the end of the war, devastating Madara and most of the Shinobi Alliance and then creating the final arc.
I suggested that Oro would use the Hokage against the village several times and got burned for it.
But that is one of my favorites for the final arc.