I think you're really oversetimating Hinata's popularity in Japan, we have multiple japanese who confirmed Hinata isn't that popular in Japan and who confirmed Sakura and Neji were more popular, they had to market the movie with Naruto Sasuke and Kakashi to make these fandoms believe they would have an active part because they knew Hinata wasn't popular enough to make people see the movie, besides NS is way more popular there so I really think this whole Hinata is more popular from Kishi is just Studio pierrot crap. Either way even if Hinata was more popular it doesn't warrant to change the character's status and your whole story to try to force her onto the plot and as the main character's love interest at the end of the manga without any build up while at the same time degrading your "heroine" just to please fans because at the end it makes your story disconnected and look like an asspull (which it is). The bad reception of this movie is proof enough that Kishi isn't really aware of what his fanbase wanted, he made a gamble and I think he failed (only time will tell), he lost a great part of his fanbase not only in Japan but also in the West and I'm not talking only about NS fans far from it. Never ever use popularity to completely rewrite the manga, Kishi made an error and I think he will soon realize it.
Perhaps. But I will not surprise if Hinata is much more popular than sakura.
Well I use the latest weekly shonen jump popularity poll. In that poll Hinata beat sakura. The poll happen to commemorate 10 year naruto anniversary.
Yes, it doesn't good and I never think he will ever do that.
But turn out to be kishi is just sellout writer and worse.
Who doesn't know how to make proper manga story.
Even by shonen standard.