I always wanted to rewrite Boruto but with a little bit of Xian Xia mixed in. I wanna explore stuff like the eight gates and the Rinnegan. I wanna see what immortality could mean for Naruto characters. Note that I will not make any Shinobi in the story some kind of immortal, just look at what it might mean, sort of like with Orochimaru.

To me Naruto should have been promoted to Chunin when he came back after the bell test. He should have been studying how to be a proper Chunin on the Tenji bridge arc clashing with Sy along the way. He should have been promoted to Special Jonin after defeating Kakazu. He should have been promoted to Jonin after defeating Pain. Tsunade should have promised him the seat of Hokage after his clone's showing against Madara, when the Kage were going up against Madara. And Finally it should have ended with Naruto being the youngest Hokage of all time.

Zabusa lost because he underestimated Naruto and Sasuke's will to fight. And even though I dislike the ending, Madara Uchiha lost because he mistook someone else's will for his own. 

Tsunade's will of fire. Might Guy's willingness to die for the future generation. Obito's will being weakened by the life he could have lived resulting in his loss. Everything was about will.