Although Sasuke dying for Naruto would be this big dramatic end, it would undermine the entire story. Naruto has not only stated that he would not become Hokage if he could not save Sasuke but that he would rather die with him that see him die. If he died for Naruto and Naruto then went on living and became Hokage it would undermine him as a character completely, everything he said would have no meaning and a lie and the character would loose all respect.
They would both have to die to make it make sense. Naruto carrying on without Sasuke when his attachment to him steps over the line of obsession would not make sense, suddenly getting over it and just thinking back to bittersweet memories would not make sense.
Also, Sasuke at this moment would have to undergo a sudden and enormous personality change to sacrifice himself and Kishi would be a fool to rob his fans of the show down between Naruto and Sasuke that people have been waiting for most of the serious.
Both Naruto and Sasuke becoming Hokage or both of them dying to save the world are the only endings that will work at this point.
I know it is morbid and I usually hate sad endings but I can't help but want them both to die, going off together as children, holding hands into the afterlife where Itachi, Jiarya and Minato are waiting for them, all there pain erased and together without malice at last.
