Allow me.
The thing is to overcome herself. She really hasn't done that. Confidence is the main issue on her character and yes, it has to do with Naruto, because he is her idol. Remember, the databook, after part 1, declared that it's admiration, arguably today as well. Now, whether you want to say it became love, well the point is that it erases the idea that part 1 she wanted love. What she want is acknowledgement that she has improved. The thing is what Naruto do, is something Hinata would like to see a hero would do. It's like "Look at him, saving that guy from the mistake. That's an idol and I'm proud of it." There's a reason why people has said that Hinata connects with everyone as friends (chapter 615), because this is her superhero, and the world has see him as a hero as well, an idol. Everyone is influenced by him, hence never give up. When you think about it, you too would be embarrassed to see your idol do something dumb because it's like "that's your hero..." Referring to the chuunin exam fight with Kiba with the fart and if you want to include the RtN prologue, same thing applies as to say, "My idol is a pervert thief...T_T"
I know all this, and I don't see what it has to do with my first point. You're talking about her admiration for him but it has nothing to do with her thinking "I would like to have a passion too." when she sees Shino and Kiba with the insects and Akamaru. This scene has nothing to do with her admiration for Naruto, she's admiring Shino and Kiba for having a passion in this cene she said it herself. "I admire them, they have a passion."
Last character to see him to go. The thing is Hinata didn't update that much because she has confidence issue, let alone can't go to see someone in the hospital. So she didn't have a good resolution. That is until the end to be motivated once more. Now, I will give you this. I too thought the same. But rereading it, it gave me an idea that NS has a chance, but I don't know if Naruto can keep up. Turns out much later of my growth, he never gives up. Ever. Also, Kishi has said that romance is something he wants to try in part 2. Again, part 2. That would mean part 1 isn't as serious as it is now. That means all can be regarded a good friendship bond from many characters, making it a usual Shounen ending with no love at the end. That has changed. For starter, Sakura is the first to meet Naruto in part 2. Took another while for Hinata to show up. Next, the whole flirt, which comes as a surprise. Then, well you know the rest. The game changer that seriously cannot be destroyed and quite honestly, something that really screwed all others horribly was the second arc of part 2, mainly Yamato's dialogue. It's the cliche work of disguise of what's already there being hidden.
You're right, and again I know all this. But still, when you look at Part 1 as a whole, if you omit some NS scenes, it looks like Kishi was going on a NH/SS road. And the fact that she was the last person who saw Naruto leaving while thinking "I won't give up Naruto" means something, it is significant.
But still, it doesn't change the fact NS is on the road since the beginning of Part 2 like you said.
It just proves that kishi sucks at romance, but not in the romance itself, because NS is well developped. Just that you can see romance in every bound in this manga, look at NaruSasu fanbase. If it was a yaoi manga, they would have the right to believe it will happen at the end.
Don't get me wrong, I love the fact that all bounds are developped a lot in naruto, but it's not easy to deal with so many one-sided love when you have to make one of them canon at the end.