I've never really found sakura that deep tbh, maybe its because kishi hasnt really developed her well
Actually Kishi has. The general misconception is that she has no power-up, no development.
Sakura went from a fangirl who didn't stand Naruto to be so close to him, to actually have romantic feelings for him.
She went through so many phases of character development as in her behavior and relationship to others that I could do an essay of it.
Not to mention that how much she changed towards Naruto...
People tend to overlook things like these because they;re not visually appealing, but to me, she is hell of a complex character.
That's why she's easily targeted for hate.