Kishi really didn't switch till the last minute to be honest. His new editors were on board with the idea since the Pain arc but he was almost always on the fence.
Basically his new editor were on board and loved hinata and wanted to make her the love interest and the heroine. So they gave kishi the idea for hinata's love confession. Kishi did it probably to get Naruto out of the position he put him in for Pain to give his breaking speech, but didn't think it would be good idea to to switch out Sakura for hinata as the heroine and the love interest. Even he probably knew it was a bad idea. So he got into arguments with his editors and got other mangaka to support him (this is information we got from that post months ago) getting them to back off. The problem is that since he did the Hinata confession he needed to do a Sakura confession along with other thing to reestablish the she IS the heroine. The problem is the nH and (to some degree) ss fans had gotten their fantasy coming true then see it quickly threatened. So embolden and nervous about their dream being under fire they sent hate mail to kishi with the intent to destroy Sakura. The editors sent the letters as well as some youtube reviews to kishi and he became surprised and was convinced that Sakura was hated by the fans. So the editors felt more confident about pushing Hinata while Kishi was less confident about Sakura then he was before.
So that led to the war arc where kishi went back and forth between showing us hinata scenes to please the fans and trying to "fix" Sakura so the fans would like her. Because he still wanted Sakura as the heroine and the love interest since she been that since the beginning and he had started to base more of her character off of his wife in part 2. But because he didn't think the fans liked her, he approved the last movie being about nH, and set up some background stuff just in case he couldn't make Sakura popular. To be honest even when he did something with hinata he barely used her at all and when he did it seemed to have a negative tone. Not that her fans cared of course since they just wanted to sexual fantasize about her. but in the end a good portion of SP wanted nH, his editors wanted nH, as far as they knew nH was beloved by the fans in the west, and the last movie was nH so the higher up told him to make it in nH. So he had to go a long as well as do those interview...and his reputation is now destroyed.
Also even he clearly thinks ss is bad but it was a "pairing the spares" thing with that mess.
Edited by Bail o' Lies, 08 December 2015 - 06:31 PM.