Jump festa Kishimoto interview 2010:
Kishimoto: Sasuke's becoming more and more evil, and him fighting with Naruto will probably be the last event
Jump festa 2012 Kishimoto interview:
Question: What is going to happen to Sasuke next year?
Kishimoto: There is still much story behind Sasuke. His appearance will be more frequent next year.
Question: Has it been fixed from the start that Sasuke should leave the village to be what he is now?
Kishimoto: “Yes its from the start. There were the same old stories in which an enemy turns to a friend and I wanted to write a story where an once friend becomes an enemy.”