Prediction: Sasukes role in defeating Madara
SPOILER!!!, just In case you haven't read the most recent chapter of the Manga.
I think that Sasuke is going to have a major role to play in the upcoming conflict with Madara. Consider the following:
1. Madara is apparently on a level that virtually no individual ninja in the world could deal with, even the 4th Hokage said he wasn't equipped to deal with Madara and thus sealed Kyubbi in Naruto to make a person with a unique set of abilities.
2. Sasuke is now on an extremely high level of power, able to hold his own against several kages and supporting ninja at the same time (it's likely that the alliance of villages will need every edge to fight against Madara, and I would say that Sasuke would be a key player depending on what faction he sides with)
3. According to Madara, The Sage had 2 sons that were at odds with eachother and that they and their descendents were fated to hate and oppose each other. He stated that Sasuke and apparently all Uchiha come from one of these 2 lineages. The 1st hokage was part of the other lineage, which is why Madara and the 1st were destined to come into conflict. Madara has also stated that Naruto has the same spirit as that lineage that the 1st hokage is part of, and counts him as part of that lineage. This is why he says that it is Sasuke's and Naruto's fate/destiny to hate and be in conflict with each other.
4. Naruto, has on several occasions broken or changed various peoples destinies/fates, including: his own (by becoming accepted and loved despite being an orphaned misfit with the fox sealed in him), Gaara, Neji, Tsunade (by being the factor that changes her outlook and gets her to become the 5th hokage), and Pain/Nagato. Naruto is exceedinly proficient at changing peoples hearts and outlooks on life and the world.
5. The enemy of my enemy is my friend (Madara is now the enemy and greatest threat to the entire world).
My prediction: By stating that Naruto and Sasuke are fated to be opposed to eachother and in conflice, they are setting it up for Naruto to break that fate and help redeem Sasuke. I expect that Sasuke will some how come around and hold a pivitol role in defeating Madara.