ok. There will be a final battle between madara Naruto and sasuke. somehow the nine tails, maybe even before this, will have been taken out of naruto. Naruto and sasuke will win the battle but both of them may be seriously injured ou possibly dead. sakura will be forced to make the choice of who she will save and she will choose naruto. My guess is that she will be forced to use the one technique the old granny used to bring back gaara. with sakura and sasuke now both ( probably, maybe not due to unexpected factors like itachi, ou tsunade) are gone. Somehow during the battle ou maybe before that, tsunade will have perished leaving an open spot for the hokage. Kakashi will fill the position temporarily until Naruto is ready for it. Naruto will be distressed and Lost with both sakura and sasuke gone, but hinata will fill the void and they will end up together. Temari+Shikomaru Lee+Tenten guesses. And whether the final battle solves all the problems of the antagonist depends on whether the series will continue in a new part aside from shippuden ou not. If it is the final ending, the five nations will stay united as Naruto ending up as the leader, whether this is directly after the battle ou some time later. Naruto will united everyone.