As we all know, one of the main topics of the second part of Naruto was finding a way to break the "curse of hatred" that plagues the shinobi world. Kishi somehow considered it broken by two sons of Hagoromo finally working together and by the peace that came after the last shinobi war.

The problem is that the power of the nations is really unballanced after that-Konoha has by far the strongest shinobi and on top of that is the only village that has a bijuu. This is sure to eventually bring conflict between the new generations of shinobi once the ideals of the shinobi alliance are forgotten. Thinking about this, I came with a more permanent solution using one of the most broken jutsu in Narutoverse.

I'm talking about Rinnegan's ability to ressurect the dead. It has a huge downside though-the user dies. What's up with that then? Since it can ressurect multiple people at once (as shown by Nagato), you could use it to ressurect many people along with another Rinnegan user, dying in the process. Once you need to ressurect more people, the Rinnegan user that was ressurected uses his jutsu to ressurect more people along with the original Rinnegan user. The two shinobi with Rinnegan essentially swap places every time their powers are needed.

How do you get a second Rinnegan though? The only two Rinnegans in the world are Sasuke's and Madara's. To use both of them, Sauce needs to ressurect Madara, after which Naruto defeats him and takes his eyes. Naruto should be even more compatible than Nagato, so there's no problem with that. We also know that people ressurected by the Rinnegan keep their transplanted eyes, as shown when Kakashi kept Obito's Sharingan in Pain arc.

Now every time somebody dies in a battle, either Naruto or Sasuke (depending on who's alive at the time) ressurects them. Eventually the countries get tired of fighting wars where nobody dies and give up. Suck it up Kishi, your manga has a shitton of plot holes.