This is the only point I'm going to respond to because otherwise we're going to be here all day and the fanfiction already exists anyway. The fact that you thought that this was at all a good argument says so much about you. You're assuming that Sakura has permanently friendzoned Naruto and only loves Sasuke because that is what you think for whatever reason. That isn't what most people who like Naruto and Sakura think. So you see it as the bench scene creating a sudden 180 turnaround wow I love Naruto now. No.
Sakura in the story is very, very close to Naruto. He is her most precious person. If you want to argue that Sasuke is, then why then did she attempt to kill Sasuke to protect Naruto? And do not say it's because she loved him too much to let him be evil. That was an absolutely ridiculous claim made by the canon, because it postulates a level of love sufficient to want to kill someone who is in darkness, but not sufficient to actually carry out that murder attempt. That is not at all compelling.
So if Naruto is Sakura's most precious person, but she thinks she loves Sasuke, you can see why people think learning about the bench scene would suddenly flip her views. It's not ridiculous at all. If Naruto is her most precious person, then him being a romantic partner of hers only requires chemistry. And you can easily get chemistry. They had romantic moments in the story.
The bench scene would have been absolutely massive for Sakura. It tells her that Sasuke is willing to come out of his shell just for her. That he likes her.He's attracted to her. Not just to her, but to her imperfections. Not just to her imperfections, but to the one imperfection she absolutely hates. It gives the impression he understands her, when the real Sasuke absolutely did not, but Naruto ironically did. Sakura would have been left with the impression that Sasuke secretly felt a certain way, but was just too shy to do anything after that. That is just horrible to think about if you are Naruto, or even if you are Sakura. I hope you actually understand it now. But I don't have anything else to say to you.
Doctor K in the house with your daily dose of "turn down for what"!!!
But seriously, this is a very well crafted post, and I quite frankly don't have anything but praise for this.
Now, don't let the creative juices stop... Here's my own version:
I remember a scene in where Naruto was sitting in the bench mourning Jiraiya. I am not sure if Sakura was there at one time with Naruto, but I imagine them just being there in the bench, talking and supporting each other as they have always done. I can imagine them talking about whatever happened to Sasuke and during the conversation, one of them brings out this scene. To me, it has to be Sakura because this would start to trigger closure on her feelings. During the conversation I imagine her talking about how she wanted to be acknowledged by Sasuke and about the comment on her forehead. Considering how clumsy Naruto is, I can imagine him trying to support her and blurting out something like "and you still have a charming forehead". Of course, this would make Sakura realize why Sasuke acted in two different ways in the same day (1-Charming forehead and 2-You're annoying), because the 1st was never Sasuke in the first place. With her Tsundere behavior, I imagine her pulling a "post-Pain" scene: she punches Naruto in the head but proceeds to hold him too, realizing that it was this "baka" who was the one who was always there, encouraging her and of course, the one who gave her confidence from the start ("fake" confession resolved and bench scene resolved: two birds with one stone). From here out, let the romantic scene play however it goes best with them. I can even imagine Naruto trying to kiss her only to receive a punch, but Sakura telling her that he can at least kiss her forehead (after all, Naruto has dreamed of this all along, but Sakura may still consider him a bit of a pervert. Hence why things would not go so fast).
Yeah, that's more or less my take on it. Anyway, I have seen a few ideas, but bring out the creative juices people. :)