Kishimoto has purposely made him as ambiguous as possible so you can't classify him as good or evil. He can't kill secondary characters so him killing an actual main character is laughable. Naruto's biggest concern is for the redemption of Sasuke and bringing him back. Eventually he will baptize him and make Sasuke see the light and convert to his peaceful movement. It'll be sunshine and rainbows from there.
You see nothing wrong with joining someone that killed the Third hokage and attacked the leaf for power? Betraying all of his friends.
Nothing wrong with joining a group that killed several leaf ninja? Kidnapping someone that was minding their own buisness, protecting their village? Wanting to go and destroy the leaf and anyone that questioned his ways, until interupted by Madara? Trying to kill your former team member twice? Then of course the recent one with chapter 460?
What do you need to classify someone as a villain in a story?
Kishimoto has purposely, if you see it that way, done such up until now. Read the latest spoilers if you have not.