When I look at it very closely, I think Sakura and Sasuke have a sibling relationship too. I mean, when Sasuke left and Sakura tried to stop him, she tried her best to make him stay. Wouldn't you do that for your brother? And she looked up to him, just like a little sister would and it made her ambitious. And she punched Sai for insulting him. If someone was saying stuff about your brother, wouldn't you have gotten defensive? Sasuke seems like the older brother with the "OMG, my little sister is so annoying" attitude and Sakura seems like the little sister adoring and asking for recognition. And I also think NaruSaku has a romantic relationship. I mean I think people have been watching too much romantic dramas or something like that. Relationships hardly ever happen where a girl likes the guy SOOOO much and the guy finally accepts her feelings. I reality, loving and trying to get someone to love you back is only a burden to them. And if they were to get together, I think the relationship would be short-lived. With Naruto and Sakura, they have like a friendship and caring relationship. I personally think this is the strongest. They could have common ground and relate to each other, and it wouldn't be awkward to hang out with one another. I think slowly this kind of relationship grows until they learn to love each other, and then their bond will be extremely strong.