There is one HUGE logical part, and one of the reasons Sasuke CAN'T go back to being good or part of the leaf village. During the Kage summit, Gaara tried to convince Sasuke to change to the light and not wander in the shadows. The point was made that Sasuke is wanted on multiple accounts. I could see him serving a death sentance for his crimes. He also became a tratior to the leaf village and only very FEW people would want him back. In all reality and logic, Sasuke hasn't a reason to become a good guy again. But I do think that near the end of the story, Naruto and Sasuke will OF COURSE have a final battle. Naruto will begin to lose until he pulls an ace out of no where, beat the crap out of Sasuke for awhile...but in the end, Sasuke will see the light once more, but end up dying...either that or they both will die, OR Naruto dies, and Sasuke lives on as a shadow and becomes 'blind' or something, making him harmless...