Quite honestly, I am very disappointed in Kishimoto as a storyteller.
This ending was rushed, and there were so many random developments and pairings that had no build-up. Some didn't even make any sense at all. He also committed a complete character assassination of both Naruto and Sakura.
I will keep H&E running for as long as people want to post about NaruSaku, but I will not be reading any more of Kishimoto's work, nor will I be watching the Last movie. It's just going to be Kishi's way of justifying the complete lack of NaruHina/SasuSaku development over the past 15 years.
This was indeed a shocking ending. Shockingly bad.
This reminds me of a fan theory to explain what happened to "How I Met Your Mother".
The writers had the story for the first season, and how it would end.
The series became successful, so the writers had to let the characters develop and evolve to fill out the middle seasons. But they made the decision to stick with their original ending, so they had to ignore all the work that happened between the early and last seasons to make it fit.
That's how it feels for Naruto. Rather than decide to adjust his ending to be a natural resolution of all that has happened during Shippuden, it feels like he decided stick to to his initial (under developed) ending.