Wait, really? I haven't paid attention to a single thing regarding Naruto in years, so I've missed all this. Like, he legitimately admits he had no idea what he was doing, was just out to make a popular franchise and just did whatever the editors said?
Because if that's legit and it's not just being assumed that's what happened, that honestly explains literally everything, including the fact the kittening series couldn't decide on an actual antagonist to save its life.
I think I should probably clarifiy this. This is based off an interview with Kishimoto that took place shortly after the Boruto movie was released. I believe it got into the creative process, and Kishimoto first mentioned the pilot, where Naruto was an old man making ramen (Kyuubi was in it in some capacity); Yahigi thought it was dumb and put in the ninja, therefore the very premise of Naruto was never his idea. He went on about how originally it would have just been Naruto and Kakashi; Yahigi again suggested a rival (Sasuke) and a love interest (Sakura...or also Sasuke, depending on how you view things). Kishimoto originally wanted several small arcs with missions (I will agree with him on this one), but Yahigi again suggested the chunin exam arc to up the popularity and add several new characters at once. Kishimoto also admitted having trouble coming up with a villain, and guess whose idea it was to put in Orochimaru? Here's a hint: it starts with a Y. He also suggested Jiraya, and I assume Tsunade, to the series. The timeskip was also his idea.
So, I won't say it was a full list of "his idea, not mine", but when you see that pattern, it can't be a coincidence.
The revelation from this interview hurt me a lot more than the outcome of the canon pairings. It's one thing when a writer makes a kitten ending to a series, but it's another when you learn nothing about the series that made it special was even their idea. As you said, it was a house of cards that was going to fall at any time.
It also explains why we haven't heard from his Sci-Fi manga. None of the other editors were as generous as Yahigi; most may suggest ways tot make the story better or more marketable, but Yahigi practically wrote the damn thing for a long time. From what I understand, Kishimoto pitched several series during the war arc, but none were picked up.
He doesn't have the excuse of being too busy with Boruto. The current creative team just asks him "Is this okay?" and he approves it or not. He gave the current artist full reign on Sarada's...interesting clothes, and it's Ikemoto who oversees the anime. It feels like he's not doing his own thing right now because he literally can't find work anywhere else.
Meanwhile, you have Hiro Mashima who finished Fairy Tail only a year ago. While some may have been disappointed by the ending, it was certainly less controversial than Naruto's was. He's currently working on Eden's Zero, AND he's overseeing several Fairy Tail spin-offs.
RulesofNature said this somewhere before, but given his time on Naruto, Kishimoto should be considered a veteran in the industry, not some new author who may or may not pan out; his lack of new work since the end of Naruto seems like a red flag that something went wrong with his planned project.
Naruto the Last is basically Hinata replacing Kushina as Naruto's mother, isn't it? Would explain her being upset at the scarf, or him being guilt tripped into doing what Hinata wants.
There was a mock review on Tumblr (a kind of Q&A) about the Last, and around the genjutsu scene the guy mentions that they make Sakura like Kushina by making her more of a mother figure to Naruto instead of the girlfriend Kushina wanted him to find.