This is possible, but if Naruto and Sasuke go to fight Madara together, remember that he has the power of several tailed beasts (it's still unclear whether he will gain the Eight-Tails or Nine-Tails, and if he does, Naruto will most likely survive the extraction the same way Kushina did in chapter 501), and Naruto and Sasuke are going to need a strategy to take them all down (if of course, they do team up, which also is doubtful at this point).
But to me, considering all the power Naruto has gotten lately from taking control of the Nine-Tailed Fox's chakra, I think Madara has another weapon besides the tailed beasts - the yin portion of the fox's chakra, the one that Minato sealed away. I don't exactly know how Madara would be able to get it, but if he does have possession of it, he might try to use it against Naruto to disrupt the harmony flowing through his body, so to speak. I also think Madara has the yin half because he needs it for his Moon's Eye Plan (resurrecting the Jubi), and the fact that his plan can't move forward it without.
Sasuke's fate at this point is most likely death, as you have stated killing innocent people with no show of remorse, but if by the conclusion of the war he decides to take the side of the Shinobi Alliance, then Naruto (if he becomes Hokage) might be able to engineer Sasuke's return to Konoha, albeit through heavy protest from the other great nations. But that would be wishing. No doubt Naruto has experienced loss in his life, but having Sasuke killed would be the greatest one yet. But even still, considering Naruto has triumphed over his true self, is he capable of hatred anymore? That's a question I would want to have answered by the time the Fourth Shinobi War begins. If Naruto sees his comrades all around him dying, will it elicit anger from him? Most likely not, because the days for that are long gone. Naruto is going to keep his sangfroid, and that will be the demise of his enemies. I wonder, though, what are Kishimoto's plans for this war that is on the eve of beginning? Are the five great nations going to become one titanic battlefield? Are entire villages going to be crushed by the step of a tailed beast? Is the Jubi actually going to be revived, or will Madara die before his plans are completed? And what of Kabuto? Apparently he is trying to play both sides aginst each other so he can emerge victorious in the end for his own personal gain. Kishimoto has much to reveal.
