Well , the thing is a good manga has a scaling plot. Every threat needs to be greater that the last. Right now we have a revived mega villain alongside full of vengeful spirits "sidekick" (who is actually top3) that wants to place the whole world under an illusion and uses an ancient monster of destructive power to achieve that. If there is one more arc, we need something to top that , which would be kinda difficult. Or, we have a timeskip, like 30 years after the war, the villages again become enemies and Sasuke takes on Tsuki no Me.