Then at that point, he is failing to tell a story.
Naruto's entire motivation was his friends. You can't conclude the story without addressing them.
The Bijuu are directly tied to the Cycle of Human Suffering. They began to look hatefully upon people because they were used for power and destruction, deprived of freedom. You can't end the series without explaining what happens to them.
You can't end the series without showing the world at peace in some context. Kaguya and Madara -just- happened. The notion of 'war' and 'peace' have been undertones since the beginning of the series and the overtone since Naruto's training under Jiraiya and the whole "Child of Prophecy" thing.
You literally can't fail to expand on those elements.
Many of the others he could simply neglect to explain...
But I have my doubts. Names and the 'obscurely obvious' have been Kishimoto's favorite things to play around with.
Shinto and Buddhism have been beaten to a pulp by the series. Things are about to get a little Taoist around here:
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This explains the Naruto Universe.
At first I thought it was purely a weird Taoist 'nod.' But then it became more obvious as I began digging deeper into Shinto and Buddhist teachings.
At the core of Japanese Buddhism is a Taoist model of the physical and divine universe. This is symbolized by the 'old' Yin and Yang symbol in the center - the spiral. This symbolizes the mixing of Taiji (divine inspiration) with Wuji (the formless infinite) to create the cycle of Yin and Yang. This produces the four movements which in turn create the Eight Trigrams - or Bagua; the core phases of the mundane world.
I just thought it was weird that the Bagua were illustrated as triangles... and that square always seemed a bit odd.
Then it hit me while researching Hidan and the symbols used for Jashinism. The square in the upper left hand corner is the symbol for Amaterasu - the Sun Goddess. The circle formed from the spiral is the symbol for Tsukuyomi - the Moon God. The triangle forming the Bagua is the symbol for Susano'o - or the God of the Stars (also God of the Tempest).
This fits in perfectly with the notion under Taoist depictions of Yin/Yang cycles being embodied by the Moon - which continually shifts from fully bright (yang) to fully dark (yin). The Bagua can actually be said to relate to different phases of the moon based on their relative composition and hierarchy of yin/yang composition (whether Yang is building or Yin is returning).
This also ties into Infinite Tsukuyomi and the concept of 'Divine Presence' or 'awareness.'
Amaterasu rules the state of divine presence - the state of divine consciousness and wakefulness. Tsukuyomi rules the state of sleeping and dreaming - when we are focused on the day-to-day and the mundane. Susano'o rules the stars that remind those who are asleep to wake up and to guide them to a state of awareness (from back when stars were navigational aids).
Thus, it would make sense that Susano'o prevents one from falling under IT - which is a state of continually being ruled by a dream world.
Although Kaguya should have never been sealed. Bad things are about to transpire because she was.