So what if he is good? I'd actually rather have him go back to what he was starting to become before he decided to go with Orochimaru. Which was a ninja that had morals and also respect/loyalty for another teammate or a friend. Hebi Sasuke/ "evil" Sasuke had selfish and pretty childish ideals, had almost no morals, and had no respect or loyalty. He was walking a path to not only the destruction of things around him, but himself. You might be asking how someone bent on killing people is childish, but think about it. He'd rather kill and destroy his obstetrical, rather than wait and talk through some of them. He would rather rush right into instant gratification for a few moments than wait. Kids do that a lot of the time, and then regret it. Just like how he rushed off to get power quickly, he regrets leaving. Just like how he killed Itachi, he really regrets that. Just how he tried to kill his teammates, twice, and refused Naruto's help many times.. He probably regrets that as well.
Point is, this kid has now grown up. He knows everything there is to know about this world. The only unpredictable part of his future is going to be the people living in it. He knows Naruto still views him as practically a brother and that the rest of the team accepted him back. He has a reason to stick around, more than ever now since it's up to him to end the Uchiha fate of hate and to help keep the rest of the world in line.
