And yes, I believe the only difference between LS and NH is popularity. Lee does the exact same thing with Sakura, risking his life to protect her, but his actions doesn't get as much applause as Hinata does in the pairing base. LS is much healthier and probable than SS, yet pairing fans thinks SS will have a bigger chance of happening. It's all about what the pairing fans prefer. Pairing fans don't want to root for Lee, because he's not handsome or overpowered or anything.
I agree with you. Hinata's popularity is astonishing to me, especially when the qualities she is praised and defended for are also demonstratred by Lee. Where is the committed outrage that Lee's feelings aren't the deciding factor of the manga? /sarcasm
But I have to say I do root for Lee! I love Lee. I wish his feelings for Sakura could be returned, because let's face it, Sakura could do a lot worse than Lee. But as much as I like Lee, I can't support him winning Sakura at the cost of Naruto's feelings. My support of Naruto is unwavering and absolute.

And to be honest when I was a SS fan, I only rooted for the pairing because Sasuke was cool and handsome and strong that I wanted him to have a pretty girlfriend.
That's interesting. I liked Sasuke in Part I, in the sense that he had an intriguing backstory and his attitude was so the opposite of Naruto. But I NEVER liked him for Sakura, for the simple reason that although Sasuke showed a grudging acceptance / respect / bond with Naruto, he was always cold and condescending toward Sakura. Even during Sakura's hysterical fangirling stage, I never bought SS as the possible end game. There was no chemistry and zero mojo, while NS had it in spades -- despite Sakura's determination to believe in Sasuke as a White Knight. I couldn't care less about seeing Sasuke win the affection of a nice (if misguided) girl, especially at the expense of Naruto's feelings and dreams.
As for the "what makes a crack pairing" debate, surely the deciding factor is authorial intent? I don't consider any pairing that the author implies as meaningful in the formation of his/her characters, or that he/she purposely uses to confuse readers as to the characters' true feelings, to be crack -- whether it is one-sided or not. If the author develops the pairing in some form to add dimension to the plot or the characters, it is not crack. So to me, NH, SS, LS, and NS (obviously) are not crack.
Crack pairings are those that fans ship purely for shock, kicks, or whatever. They are pairings formed between characters who have demonstrated no romantic interaction in the story, or may not have even met, or who hate each other, or maybe are paired randomly just based on physical attributes. Crack pairings usually involve a highly sexualized component, manufactured angst, or the use of canon conflict between the characters for the sake of fan titillation.
Pairings Gaara/Lee, Gaara/Sai, Kakashi/Sakura, Itachi/Sakura, Kankuro/Sakura, Sasuke/Hinata, Tenten/Hinata, etc., are pure crack, in my opinion. Nothing wrong with liking them, or playing around with them in fan fiction, but they're crack.