First off, I'm not really an SS fan, nor have I ever been. In fact, when I first started reading the manga ages ago, I had seen artwork on dA about SS and was surprised to find it was not supported in the series. At all.
But after reading a few really good SS fanfics, I found that I didn't mind SS...only if Sasuke was changed from the way he was in the manga. Which is sort of like cheating, right! :)
So here's how the character developement would have to go down, for me, to switch the roles to move Naruto out of the triangle so that Sakura becomes more important to Sasuke, and Sasuke becomes more important to Sakura:
— Sakura doesn't have to change too much. Her normal manga character evolution from crushing young girl to powerful, self-assured young woman is still good. But maybe she's a bit more serious, and sees more clearly the burden Sasuke carries and that Naruto's bond is one of friendship when they were children, but that as an adult things are not so clear cut. So she fills a role of understanding that Naruto cannot fulfill for Sasuke. (This is important because she has to move up to a place of greater importance in Sasuke's life than Naruto.)
— Sasuke has to more sensitive from the beginning. More overtly empathetic towards Sakura, even if it's just a few isolated moments and even if it's just in private. But the basis has to be there from the beginning. Then later, when they cross paths, there has to be some pause in him when it comes to her. She doesn't even have to be aware, but there still has to be a connection he can't seem to shake. Then much later, if they have an aggressive interaction, Sasuke must either hold himself back or step in at last moment to protect her from something/someone else. This is important because it takes the place of the "my body just moved on its own" connection he had to Naruto and shows that Sakura has managed to be the bond Sasuke has kept from Konoha. Not his connection to Naruto. From there, it doesn't matter how Sasuke chooses to acknowledge those feelings, because it's all up from that first turning point of going out of his way to keep her from harm.
— Naruto has to be stuck in his goofy immature powerhouse role. He doesn't develop like Sakura does into a responsible, far-seeing person. Instead, Naruto is the one who still clowns around most of the time and then shows up to blow everyone else away. When the action is over, he goes back to his loveable goofy self who wants everyone to be friends. It becomes clear that Naruto really doesn't understand the burden Sasuke carries the way Sakura does. (Again, important for switching the roles around so that Sakura is more important.)
— Hinata would serve as a sort of quiet, gentle minder for Naruto, off-setting his brash silliness with her gentle ways. Both her and Naruto would be more immature, less dynamic characters than SS, in this scenario.
So the reason I think it has to go this route is that there is no convincing way to make SS work otherwise. I've read a few fics where Naruto comes on the scene as himself, without taking a step back from the triangle, and he simply overwhelms the dynamic. There is no convincing reason for Sakura not to be with Naruto!
I know this is detailed, but I've thought a lot about it due to writing fics, and making sure the relationships are convincing. It's almost like connecting the dots. Once the foundation is there, the true love can be hidden or can take a while to develop, but it's always there. The two characters are always growing towards it, even when they think they're not.
Another thing, I am much more comfortable with envisioning SS than I am NH. SS is based on evolution of characters, with tragic events shaping their lives. Sakura betters herself to reach out to Sasuke, and Sasuke could find unexpected healing of his wounds with Sakura's loyalty and compassion. If written well enough, they could fit together.
But Naruto and Hinata would never fit. Hinata is not a character based on change or development. She is a stereotype. It's not the same as changing Sasuke. Hinata would have to be a completely different character, not just a few tweaks to the storyline or a little more depth of character. Take Hinata out of this story and put her in any other one, and she'd still be a background character. Simply put, she'd have to have Sakura's character development to make her be a lead.
So it's much easier for me to envision and even read SS fics than it is NH. As long as Sasuke is more compassionate, I can read it. I guess it's like a Beauty and the Beast story vs. a self-insert. NH stories invariable seem to be about Hinata or those who want to be like her! 
Persona 5 hype 
