Sasuke was never evil. Konoha is an arbitrary establishment. It has committed heinous crimes against many ninjas, Uchiha Clan included, who happen to the one of the founding fathers, and that is just like scraping the tip of a very large iceberg. These Villages are in the way of peace themselves. Committing terrorism against others and their own people, committing espionage activities, amassing techniques - all during the period when peace treaties were in affect. Simply to keep the funds from the main governments that rule the countries active.
If peace completely prevailed, military divisions and their funds would be cut back, and all these hidden villages would completely lose meaning. The Uchiha massacre was one such leaf in the long book of strife between villages and their internal power tussles. All this was proven during the Kage summit harsh exchanges. Danzo's free reign to carry out utterly despicable activities cements my point even further.
Then we have the Senju, who monopolized the entire political establishment in Konoha to their favour. Other villages simply mimicked what Tobirama and Hashirama had paved way for - an arms-race and a nexus of killers for formally hired-endless espionage against countries. Tobirama endlessly persecuted Uchiha and never let go of the hatred that plagued him. I see everyone blaming Madara, and yet, Senju clan NEVER earned their place in the peace process.
It were the Uchiha that forever strove to maintain it despite Tobirama's gross and underhanded tactics of keeping surveillance on a fellow founding clan, when he had no rights, political, ethical, moral or otherwise. It was completely against the truce they mutually signed. The Senju clan completely desecrated the original concept on which Konoha was built. Furthermore, Tobirama's dictatorial set-up was passed on to Danzo, Elders, and Hizuren, who were equally responsible.
Konoha, for these crimes alone should be wiped off the face of the earth. Danzo was given open liberty to kill targets from other hidden villages who simply had a harsh political stance towards Konoha. This was proven through Sai's arc. Not only that, he gave away the Anbu Squad book, consorted with an international terrorist, and was on the forefront with his policies concerning the Uchihas along with Elders - all of them were followers of Tobirama's political setup.
And that is just a short list of his colossal criminal acts. I haven't even touched upon Kabuto, a woman wantonly killed when she ran an orphanage, and killing of Yahiko who was the original leader of Akatsuki through yet another political conspiracy with Hanzo, and god knows how many else he dispatched in the process.
By and by, this 'Evil' word for Uchiha Clan is very immature and nonsensical, when there is overwhelming evidence against this. Look at the bigger picture here. If one incorporates all practices concerning Konoha, 'Will of Fire' seems like some sort of Ugly 'Black Humour' which is so distasteful, cruel, and despicable that one doesn't even want to laugh. And somehow, the disgustingly ironic reality is that Naruto wins hearts through it and so have many others.
Utterly disgusting. The answer to your question : Sasuke was never evil. Not once during the entire Manga.
