Since I cant imagine what's going to happen next, I'll just throw in something. I don't think sasuke is the final villain. Tobi and/or Madara is. That's why this fight will reveal something. Sasuke seems to be affected by his memories, revealing a smile. That could mean the beginning of resolve. Now, will they kill Kabuto? I hope they push Kabuto so far that he needs to summon Madara. That would be awesome!
And further along, I think Sasuke and Naruto will fight. But they might end up breaking the chain of hatred. And both turning to Tobi/Madara who later on, becomes even stronger than they both are right now. If Sasuke and Naruto's fight is the end of Naruto, I'll be disappointed to say the least..