Don't believe me that Sasuke is going to be seen as a hero? Here are some things he's done recently:
1) Helped Itachi end Edo Tensei (the other kages said that whoever ended the technique is a hero. This is Itachi and Sasuke)
2) He killed the original white zetsu, and killed several individual zetsu clones (not a huge amount, but it is on the side of the alliance)
3) He has brought several old enemies (Taka, Orochimaru) to the battlefield as allies
4) He has brought the previous hokage to the battlefield, as allies
5) He is currently standing with Naruto, preparing to lead a significant attack against the enemy
Now, look at the "crimes" that Sasuke has committed:
1) He left the village when people didn't want him to. Both Jiraya and Tsunade had both left the village for various reasons in the past. Jiraya was offered the position of hokage anyway, despite his absence. Tsunade was eventually hunted down and turned into the fifth hokage.
2) He attacked the kage summit. This is his biggest crime. He didn't kill any of the kage but he did kill several samurai and caused a serious injury to the raikage. Of course, he was acting under orders from Tobi.
3) He killed Danzo. But then again, Danzo was a shady dude who was working with Orochimaru, who planned and ordered the Uchiha massacre, and was guilty of doing a lot of other dirty things (trying to have Kabuto's adoptive mother assassinate Kabuto, etc)
4) After the battle with Danzo, Sasuke attempted to kill Sakura.
Looking at the balance sheet, Sasuke is already more hero than villain. If he helps protect people and plays a decisive role in the defeat of Madara, he will be even more of a hero.
Where is Orochimaru? It doesn't appear that he came to this battlefield. Did he go somewhere else, like to help Tsunade? That would be a great way for Orochimaru to redeem himself too. I don't think he'd ever become hokage, but he could be seen as an ally and not as an enemy.
