I think the main issue, is that you don't see what makes the Chuunin Exams special.
It Does a lot to establish the sort of patterns you see later, intense reactions from Naruto. No, Naruto's cheering for Hinata in her fight with Neji wasn't about getting her killed, or that he didn't care about her well-being, it was creating encouragement, a pattern you see really from him to her. Neji, really enraged by this defiance, then tries to kill her. This later drives Naruto to his blood oath, a pretty intense reaction. This fight is also where Naruto really starts to notice her, where Rock Lee says the two are similar, and that Sakura says that she was always watching him.
And what makes the Proud Failure Speech special, on the heels of this, is that Naruto is vulnerable around her. He reveals his worries, he's even taken a detour to the exams, and how unsure he is. I think its also noteworthy after the Neji fight that he searches for Hinata's face in the crowd of spectators, wondering if she saw.
No, nothing about your words was a "stylistic device" originally, and for what you are trying to say, its the wrong phrase to use as well.
I'm adding detail to my writing, because you make a statement, and then you base source material after it. Rather than making a statement...and not adding anything to it.
I still see nothing that suggests why NaruIno can work. You haven't really said -why-.
This will be a shorter answer, because I have no passion left to argue with you and I apologize in advance for my aggressive tone:
Do you know what your problem is? You look at every scene of the two with pairing goggles and interpret it positively, something you don't do with other scenes.
The preliminaries and the first two rounds do NOTHING in favor of NH.
He doesn't care about her, he uses (unintentionally) his influence on her to confirm his thoughts about fate and doesn't even realize afterwards what he did to her, still fixated on 'fate' and showing it Neji. That 'avanging-theme' is the minimum he could have done in that situation with his character we have at hand at that point.
The proud failure speech is the only real 100% NH scene, and there are many positive things wrapping Hinata in the chuunin exams up:
He sees her now as a good friend, we are now more exactly shown what she thinks about Naruto and she manages to restore his spirit.
But you know what? It is still overshadowed by what happened in the preliminaries.
And, only because it is you, let's look at one important point with extremely unfair 'Anti-NH' goggles:
The speech is intentionally segmented in a way, that shows us that she knows nothing more about Naruto than his unwavering will. She doesn't believe in him and is only interested in her picture of him that gives her hope.
Now again a bit more serious:
The most important thing is: The proud failure speech would be a such a nice and beautiful NH scene, if it would have had any impact later on the NH relationship. It is later like it never happened and it is never taken up again and gets completely forgotten.
Oh PLEASE excuse my not perfect English, my third not-native language, I apologize that I am not running around with a dictionary to check every word.
Seriously, you doubt my personal social intelligence, passive-aggressively attack me and get upset because I showed you that it was wrong and call out my bad English?
Sorry, but you are too full of yourself. This is my last answer ever to you, it is not worth any of my time, have fun in life with that attitude.