Your 698 picture works, except Sakura does love Sasuke, and it is love the reason why Sakura wants to save him. I don't think the love dies after he is saved, which is why Kishimoto chose to have Sakura do what she did in 699. He could have done other things: Have her not act on it because it wasn't the time, It's not necessary they end up together. But this element exists, and needs resolution in some way. If everyone dies, as an exaggerated example, it's resolved: It can't happen, because they're dead. Sasuke could have said that he wasn't worth her love as another example, or Sakura could have seen that his healing would take too long, and it could be explained that despite her love for him, she didn't want to pursue a relationship.
I agree that Sakura does love Sasuke and that her love does need resolution in some way. However, I would submit to you that if the author is willing to allow a movie devoted to wrapping up all of the pairing issues, this can readily be done in a fashion that makes sense and that results in NS. But before we get into that, I'd like to note that our concern here is coming with a way of resolving Sakura's arc that makes sense, doesn't disregard anything throughout the past 698 chapters (aside from editing some of the dialogue in 693) and syncs perfectly with series' themes.
The 699 scene works very well by the way, because of its loving meaning, and Kishimoto is great with symbolism.
The problem with the 699 scene (and SS in general, as presented in the manga) is that it makes it to where Sakura doesn't really have an arc that extends beyond the first timeskip. Yes, you've explained that she's gone from a crush on Sasuke to have a selfless desire to save him, but even if I am to grant that (and I don't, since Kakashi more or less destroys any and all character progression by saying Love doesn't need a reason!), all that would mean is that her arc ended in part 1 when she begs Sasuke not to leave and assures Naruto that they will both save Sasuke. When we look to the entirety of part 2, it's all (or rather, as of the Kage Summit Arc), it's all 'cry cry cry, Sasuke I love you and I want to save you, cry cry cry, etc etc." She gets some big moments that created the potential for something else (i.e. trying to kill Sasuke), but in the end, it doesn't amount to anything and there's no real sense of character progression in sight. You could bring up her training with Tsunade as well as well as that time she did well against Sasori (arguably Sakura's shining moment in the entire manga), but in the end, it amounts to nothing and the girl still has to watch Naruto and Sasuke's back, insecure about her self-worth.
As to symbolism . . . we'll get to that in a moment. 
The problem with the hypothetical picture is it is ignoring the direction of things taken from the last hundred or so chapters. I read this horrible fanfic where the writer made the sole change to the Last at the end, having Hinata tell Naruto that its Sakura who he should be with, then some cheesy "I love happy endings" line from Hinata. But you can't make that sole simple change, it requires a significant rewrite from the bones up.
The problem with your picture is Sakura does love Sasuke, and that does need resolution. It's not necessary for it to end in being together, that can be implied, or denied. But it exists. Karin is different. Her affection is more physical focused attraction, though she also still cares for him. It's a byproduct of another, less mentioned Karin/Sakura love triangle, though I still note that Kishimoto tends to play the hands he has no intention of using more comically, and less seriously in general.
Which is why this parting moment of clarity doesn't work for Naruto and Hinata, either. There's no romance in the manga, but there is development. Everything in the manga builds the skeleton for the romance to spring from.
To get an NS ending, you would have to kill the triangle and re-work the last three hundred chapters at the least. The Fake Confession would notably need to be different, 615 would probably need to have no hand holding or result in Hinata's death instead, and preferably no love triangle. But most of all, you would have to have an author that would want NS, and Kishimoto didn't. To get a really good NS ending, the Manga would have to be rewritten from the Chuunin exams arc to not show so much NH, IMO.
I won't call any fic horrible without actually reading it first, but I do agree with the sentiment that you can't just up and flip some dialogue around to make an NS resolution make sense in the context of the Last.
Here is how you make NS happen (1) despite the fake confession and (2) chapter 615 as well as simultaneously fix and (3) resolve Sakura's character arc all in one fell swoop: Three words: The Bench Scene. One single moment in chapter 3 can be used to fix everything. By taking the biggest weakness with Sakura's character (never explained reason for loving Sasuke), she can be written to have gone from having a crush on Sasuke to falling deeply in love with him as a result of Naruto foolishly pretending to be Sasuke, saying the words she had yearned to hear as well as nearly kissing her. All these years, she thought it was Sasuke who did all of that and was determined to be with him no matter what due to what she saw in Sasuke's eyes all those years ago. That's why she romantically loves Sasuke, according to our little rewrite here anyway! 
Bada bing, bada boom, after some drama, action and self-reflection, Naruto goes for broke and takes a second crack at what he did in chapter 3, only without the henge jutsu this time. This is perfect for the character as it brings things full circle, highlights his growth as a character by placing in the same situation he was at the start of his journey, only does things the right way this time. Following a simple "That was you" from Sakura, we get this:

Now THAT'S symbolism. 
So is this: 
Around the time this happens, everything else comes into fold.
Fake Confession: Sakura finally realizes why she was getting angry with Naruto about him accusing her of lying to herself. Because deep down, she was speaking the truth when she confessed. She just didn't realize it at the time. She also recalls what Yamato said to her on the Tenchi Bridge that one time, realizing that part of her has known the truth all along. At long last, Sakura is able to realize what love truly is. And though she will always think fondly Sasuke and remain endeared that he saved from his own inner darkness, Naruto is the one she loves and her heart is finally at ease after all of these years.

Chapter 615: Hinata loves Naruto. This is indisputable. But she also loves him enough to the point that she wants him to be happy first and foremost (which is arguably the way Naruto felt about Sakura throughout the manga). And so when Naruto reaches his lowest point in our version of the film, it is Hinata who is there to comfort Naruto as well as to tell him to get back on his feet and to be the ninja she admires the most and not give up on Sakura. Naruto then gives Hinata a tender embrace, thanks her for always supporting him, apologizes to her for never having had the courage to approach her after her confession and tries to comfort her with a "In a different life . . ." line, but Hinata sends him on his way. We then get a scene of a jealous Kiba approaching a tearful Hinata, possibly hinting at something in the future. Nonetheless, Hinata's arc is complete and, still retaining her love and admiration for Naruto, is now able to move forward without him and stand on her own two feet (which is what she needs if she's going to finally fix the problems with the Hyugga clan), arguably having surpassed the strength she saw in Naruto. At the beginning, she could walk behind him. At the end of the manga, she was able to walk alongside him. And in this film, she is finally able to walk ahead of him. Perfect conclusion for her arc, IMO. 
Themes: The next generation is always stronger than the previous and this is the especially the case for Naruto, who has succeeded his master in every area he failed:

Sasuke: His character is complete as of chapter 698. The only role he'd serve in the film is assisting Naruto both in combat and indirectly helping to wake Sakura up to her true feelings. This dude, however, doesn't care about romance. At very best, he could have at a scene at the end where he smiles at his former teammates from afar before leaving the village and reluctantly being followed by a persistent Karin. If anything were to happen between them, it'd be in a sequel.
Summary: I disagree with your conclusion. To get an NS ending, you simply have to bring up stuff that happened prior to the last 250 chapters and tie it all together with what happened in the last 250 chapters. Chapter 3 basically allows us to get Sakura to come around no matter what and Sai's multiple comments about Naruto as well as Naruto's actions in chapter 3 and throughout the manga make it pretty easy for him to get on board. The only issue is dealing with Hinata and I'd say my conclusion for her character arc is a lot more admirable than what we got in the canon. And unlike with what we got in the canon, you wouldn't need a genjutsu scarf or newly made contradictory flashbacks. Don't need to rewrite the chuunin exam arcs (or any arc for that matter).
At the very least, I feel if Hinata died in 615, the manga could have worked towards a different ending. But you would still have this Sakura and Sasuke issue, and to resolve that easily you'd have to have Sasuke die. But this all in all would make a much darker Naruto ending, as this fails one of Naruto's great goals: Saving Sasuke. So the author's choice works, and its good, not ground breaking original awe defying amazing, but it's good.
No need to kill Hinata. Just need to be willing to confront the reality that people don't always get what they want. And in Hinata's case, I'd use that in a way that actually betters the character and gives her a more robust arc (which is honestly the way it should have been done for Naruto in The Last movie as opposed to that candy-pants "you only loved me due to your rivalry" nonsense).
No need to kill Sasuke either. Honestly, I don't understand why the prospect of not ending up with the first person you like is something people have so much trouble with when Naruto himself did not get the person he liked in the actual canon. There, the solution was not to kill Sakura, so what's the deal?
Edited by ThroughWithLove, 16 July 2017 - 08:14 PM.