
Naruto loved Sakura for 698 chapters, over the course of which Kishimoto developed their relationship with the most focus and care. He set up blatant parallels to Minato/Kushina, Jiraiya/Tsunade and Obito/Rin. Characters like Yamato and Sai inferred Sakura had feelings for Naruto - this was only confirmed by the data books that mentioned how Sakura was no longer certain how she felt about Naruto, only that occasionally he would make her "heart beat faster" and yada yada. The build up was there. It undeniably was, and Naruto/Sakura is the only pairing in which the two showed genuine and mutual respect and admiration without compromising one another.
Naruto and Sakura were both very similar and yet different. I thought they complimented one another. More importantly, they could actually be themselves, and they always managed to laugh and smile around each other. There was clear affection and a level of intimacy between them, in the way that Naruto always regarded her with an affection suffix, and the way Sakura, as Sai pointed out how, was so familiar with Naruto there was no formality. They were close friends that shared a lot history; they laughed together, they went through difficult times together, and they always were thinking of each other.
The reason I could never "ship" SasuSaku or NaruHina was because they severely lacked development, or in SasuSaku's case only had negative development. Sasuke treated Sakura like crap for the vast majority of the manga, time and time again. On her own she was a headstrong kunoichi with convictions. When he part of the equation, she became a doormat, a demure little girl that allowed him to talk down to her and demean her. Forgiveness was one thing, but Sakura shouldn't have ended up with him. If not with Naruto, she should have moved on to someone else.
As for NaruHina, what irritates me about this couple is that no one seems to care what Naruto thinks or feels. Naruto wasn't attracted to Hinata, he didn't think of her as anything more than a friend, and he never had eyes for anyone but Sakura. It's not that I hate this pairing, it's that it's so underdeveloped that the only reason people seem to ship it is because Sakura is a "kitten" by comparison (which is nonsense). Hinata was one of the most intriguing characters of Part I. She had a very interesting background story and lots of potential. Kishimoto ended up relegating her to pairing fodder and had to break Team 7 to make NaruHina happen.
In 699, Sakura reverted to her 12 year old fangirl self from chapter 3. Sasuke instantly fell in love and acted like the Sasuke Naruto pretended to be in chapter 3. Naruto suddenly forgot he had been in love with Sakura for 5 years, was wholly apathetic, and fell in love with and married Hinata off panel. Yeah, we're supposed to watch a movie to make sense of that, but all that tells me is that Kishimoto changed his mind late into the game after he wrote Road to Ninja.
Also, what was the point in Karin and awakening her chakra chains to save Sasuke? What was that parallel to Sakura saving Naruto whilst Karin saved Sasuke for? NaruHina and SasuSaku must have been the intended endgame since at least 2012, and since then we had Minato infer Sakura was Naruto's girlfriend and compared her to Kushina; we had the CPR scene; Obito inferring Sakura felt very strongly about Naruto to which she was unusually silent, much like when Yamato inferred she was falling in love with him.
From 615 onwards, almost every last panel concerning Sakura had something to do with Naruto; she was always worried, concerned, panicked, relieved, praising him - what I don't get is why Kishimoto didn't give Hinata more panel time, she deserved that much at least. The fact he didn't simply gives credence to the theory he capitulated and chose to please the highest number of fans possible in Japan, where SasuSaku is the biggest hetero ship followed by NaruSaku and NaruHina.
In the end, my issue really isn't with the fact NaruSaku didn't happen. It's the way in which it didn't that I find upsetting. Naruto and Sakura didn't even interact after all was said it done. He didn't tell her how he felt, the promise wasn't brought up again - simply nothing. It's the lack of closure that will really haunt fans of this ship.