What i would like to know is did madara or even the uchiha/senju in general for that matter, know about the curse of their families or were they all unaware? Or is it something madar found out about afterwards.
I would like to think that if they did in fact know, then madara and hashiramas relationship might have been like the relationship naruto and sasuke are going to have for a while. I don't think and I hope that there won't just be one battle between sasuke and naruto. Only because it seems sasuke isn't going to turn around so soon, and it's going to take more then one battle before naruto and sasuke can understand eachother through their fists. If they indeed do have simliar relationships, that must be why madara respected and admired hashirama so much. They had a lot of time to get to understand eachother.
Only unlike madara and hashirama, naruto and sasuke will bring the feud of the families to rest.