The first thing that has to come up in any discussion about NejiHina has to be "the incest thing". It's like a law.
So here's my thoughts on it.
I don't care.
In more detail, I'd like to note that incest is defined as being legally or socially taboo. So cousin marriage isn't always incest. It depends on the culture and nation.
Personally, I find the idea squicky. People in your family are off limits; people outside of it are fair game (within reason). And I've always considered my cousins as part of my near-immediate family, even though I don't know most of them all that well. So I wouldn't consider a relationship with any of my cousins.
OTOH, I could care less what other people do as long as all the parties are of the age of consent and actually consenting. After getting involved in the debates, I've read up a bit on cousin marriage and the evidence seems pretty conclusive that the genetic risk is marginal which dispenses with another possible objection. In theory, I'm that keen on imposing my morality on others (although I'm adept at finding loopholes on why it might be appropriate, such as banning smoking in public places).
But this doesn't say anything about why I'm for NejiHina. It just dispenses with a reason why I'm not against it.
This isn't really going to be much about their scenes together. Most of their interaction was during their fight in the chuunin exam and it ended with Neji trying to kill her which isn't really good evidence that they'd be good together.:
Anyway, a lot of this is going to be really reading between the lines and not necessarily supported by the manga. (It isn't contradicted, but it's a matter of interpretation, even more so than usual.)
It starts with how I first "met" Neji.
I didn't start reading/watching Naruto from the beginning. I got into it over Christmas, watching a few episodes with a friend who is a real animaniac and was back in town for the holidays. It was kinda disjointed since he was working his way through the whole series and I could only hang out on evenings. So the first episode that I saw was when Naruto met Jiraiya and tried to get him as his teacher instead of Ebisu. Then I caught the match between Shikamaru and Temari. Then a few episodes of the fight between Gaara and Naruto. I didn't catch a solid block until Naruto's fight with Kabuto (and yeah, I missed the first part of that fight).
So the first time that I saw Neji was during the Rescue Sasuke arc. My impression of him was of the quiet, sensitive sort. He seemed introspective and probably the artistic sort. There was that line "Naruto, you have better eyes than I do" which was obviously not referring to physically, but the ability to see a person's heart. I actually kinda wondered why he was in the biz since he seemed out of place. His slim build and long hair probably contributed to my assumption. Plus, his fighting style was more graceful than the others'. Then that impression was capped off by his "death" in which he had such a beatific smile and was grateful for Naruto saving him from the darkness.
By this time, I'd managed to download most of the earlier stuff and started from the top. Not thinking of that darkness line above, I didn't really think much of it when he first appeared, although he seemed a bit out of character from what I'd remembered. But I had a real WTF moment when he had his match with Hinata. It was a real shock to see him as such a jerk. (Jerk doesn't really cover it, but this is a family-friendly board.) But the other half of the chuunin exam helped show me how he'd gotten from point A to point B in characterization, although it turned out that point B wasn't exactly where I thought it had been.
I still think he's a sensitive soul. Chibi Neji seems to reinforce that he started out as such. But the oppression of the two house system and the death of his father forced him to bury it deep. He doesn't let his soft side get exposed to many people - out of habit and out of fear. But one of those people is Hinata.
Because Hinata is safe. She's a sensitive soul on the inside and shows it on the outside. Really, it takes a certain kind of strength to keep that sensitivity in the face of people pushing her to be harder (although it probably got easier by Hanabi's apparent talent as a ninja). Despite all his insults to her, she never threw it back in his face. Instead, she tried to empathize with how
he was suffering. He wasn't ready to hear it at the time, so he tried to kill her.
Moreover, she understands ... more than anyone, even Naruto ... what he's going through. She's always been perceptive to the feelings of others. She was the only one to realize what Naruto was going through. And she had even more chances to observe Neji, including the first time that either of them saw the curse seal in action. Heck, she
told him that she knew what he was going through.
If anyone is going to mend Neji's soul, it'll be Hinata (or Naruto, but I
really don't want to go there).:
It's already on the mend, but I think it'll take more than the dual revelations of fate being changeable and his father's true fate. It's going to take time and care.
So that's why it's good for Neji. But that's only half of the equation.
Hinata has strength. She just doesn't have confidence. She's gained confidence from her match with Neji. And she's been inspired by Naruto to become better ... which isn't the same as having more confidence. She just needs somebody that's going to allow her to keep developing that confidence.
Neji isn't the only person that could be that person. (Lee also fits the bill, but I don't want to digress.) But he looks like a great choice now.
When he started out, he was a conceited jerk. He was the unquestioned leader of his team and had nothing but disdain for losers. But that all changed when Naruto rocked his world view.
He still doesn't show a whole lot of interest in interaction with others, like his team although he did help Lee with walking around once while he was recuperating. But he's less assuming.
He doesn't necessarily seem to have much respect for superiors still (although with Gai, can you blame him?), but now he's a team player. He volunteered for the "rescue Sasuke" arc and didn't seem to have any problems with taking orders from Shikamaru, despite his earlier contempt for him and the rest of Team 10.
I also like to think that he's taken his father's words to heart about needing to protect Hinata now that he's gotten off of his fate schtick. I don't think that he'd take the opportunity to stage a virtual coup. He seems willing to step into the spotlight or stay in the shadows, whichever is needed.
He's also the only character that's shown any interest in Hinata's interests. Lots of characters have shown concern for her well-being. But none have cared about what
she cares about (not counting Shino in filler). Admittedly, that interest was Naruto, but he showed interest and didn't make fun of her for it.
It's not a lot on why it's good for Hinata, but this is already a really long post and it's getting late so it'll be enough for now.