Yeah I think you are looking to negatively into this, as I don't think Kishimoto only starting to like sakura at the beginning of part 2, pretty sure he was fond of sakura from the beginning of part 1.
Also I don't think sakura held too long of a grudge against naruto for the womanly comments, as she show great concern for his wellbeing when she learnt that naruto was a jinjuriki and if he is captured by the akatsuki and has his tailed beast extracted he will die. Along with the tenchi Bridge and seeing naruto in his 4 tailed transformation followed up by yamato hinting that she feels something more for naruto.
Arguably afterwards kishimoto did afterwards was slow burning development with the sakura trying feed scene and her showing having a similar pervey side like naruto when kohonahamaru showed of the sexy no justu before doing the big hug in the pain arc.
Now arguably doing the slow burn for a series as long as naruto caused long term problems as many fans failed to see and ended up thinking hinata was the love intrest due to that big pain moment. Heck this tends to be a problem for many series that do slow burn like avatar the last airbender, as not everyone saw it coming despite obvious hints.
It probably didn't help that around this time new editors came in with an anti sakura agenda to replace sakura with hinata which probably effected the writting around sakura so much that it ended up the mess that it did. Also didn't help that kishimoto became very insecure with Sakura's popularity in the west.
Pretty sure kishimoto post ending interviews are just damage control by jump to avoid the backlash with how he made the canon couples and the not a romance manga is just a poor exuse to as to why the canon couples are so bad.
I think its fine if a series makes it that one character is in love with more than one person though they got to make it eventually clear like nisekoi did. Also kishimoto should of really addressed the love confession much sooner to make it clear that sakura was in love with naruto, but also still had some feelings for sasuke.
I do have to apologize my neutral perspective seems like soured the mood. It was never my intention. I mean, it took awhile to put the past behind me that it doesn't no longer effect my life.
Edit: For those who don't want to read my final post on this negative debate, skip down to the line breaker and read the spoiler box. I have come up with a possible NS reboot manga Kishi could serialized.
Even if it pains me to think outside the NS box, I come to a conclusion that shonen manga or I should say SJ comics in general got away with a lot of undeveloped endgame pairings since the dawn of manga serialization in Japan perhaps a century old or older.
I know the passing Akira Toriyami got away with Vegetta and Bulma. Fun fact Ramenastu translated rumors back in 2014 from 2chan (Japan's main anime forum) that Tori faced a similar situation as Kishi is that he started to get tire of DBZ and wanted to end. SJ deny it and stated DBZ was too popular to conclude, so that why Trunks was born lol. It seems like he wanted to decreased the popularity of DBZ, but like Naruto, it had too much momentum in sales.
In theory, it seem like when time Yahagi left, he and Kishi had to put Sakura on the back seat because she no longer have the role as the FML. So throughout the remaining duration of the manga, the FML role is just an empty title. Where I'm basing this off of is the interview first Kishi and Yahagi had together since the conclusion. We found out in that interview that Kishi was not found off Team Taka and Sasuke became somewhat like a second protagonist (bromance). Not for the plot... as a business transaction. The increase in Sasuke's screen time was meant to bring in more fans and sadly this might have lead up to the demise of NS.
This is why Kishi never wrote NH.
Whatever happened behind close doors, it all points into the direction that the intended female lead being paired plot has been scrapped due to traditions in the shonen genre to be self centered around action and adventure from male population. Unfortunately, pairings in traditional shonen manga are meant to create/introduce more characters. DBZ is perhaps the best example I can come up with.
Even if its been many years since I'd watched the very last episodes of Z and the non canon GT (never watched Super), I still do not know how Toriyama got away with Goku and ChiChi too. I'm not saying I dislike the pairing (I'm also GokuChi fan too). Its that these a lot of the traditional male Jump protagonist are muscles brains that either lack IQ or knowledge. I mean Goku didn't know how to tell between the opposite. Not to mention he has little to no knowledge of romance and what happens between man and woman on screen. But it had to be done in order to create characters like Gohan and Trunks.
Even in modern times, I see this happening with BlackClover which is the Aster so post to be Naruto likewise Juno has Sasuke's shadows. I put Asta in this category of muscle brain MCs not because he's Anti Magic. But it seems like his intelligence on romance is misinformed like Goku. I could be very wrong since I put BC on such a long hiatus, but during my time reading, Asta apparently wants to marry the nun that seems to raised him. Apparently, unlike Naruto, Asta is lucky to have a fangirl base. However, despite wanting to marry the nun girl, It seems like Asta's knowledge what happens between man and woman might still be premature like a toddler. I mean if you have least a kid or grandchild, that child might tell you marry when they grow up.
This is why I lose faith and romance shonen manga these days. It's a rarity to get something like Fullmetal Alchemist and Inuyasha.
Traditional shonen manga forced Kishi to put NS romance on hold to increase Sasuke popularity for the sales. In general, I heard editors do get switched out in during a long durations comics from time to time. Again in theory, it's likely Yahagi's departure has to do with Sakura not getting with Naruto.
It makes since that people are putting the blame on the 14 editors that kishi went through after Yahagi departed from Naruto.
Now putting on my NS cap once again. If Kishi loves Sakura/NS. It make absolutely sense why he would not go with that pairing at the end besides the pairing not being popular outside of Japan in his favor. If he's unable to write Naruto and Sakura as a proper couple. Kishi knew it would be a disgrace if he had done a cop out version of NS because of tradition relating to classic shonen manga. That's why we have this atrocity aftermath of 700 chapter in the final chapter. That's Kishi's message to us fans, writing/illustrating Naruto for 15 years.
Now putting this terrible past behind us. I know there is a thread that topics about a what a reboot of Naruto should be like. I'm not sure if I'm going to be as active as I am in the future so I going to give my ideas on what a Naruto reboot should be like.