Sakura swings back and forth between wanting to be independent and relying on others. Her character at the start was made to succumb to others and feel hopeless. Even though she had all the tools by her side to fight for what she wanted, her constant need to rely on others, annoyed many people.
Most people criticize that Sakura was obsessed with Sasuke, and was never in love. However, Sakura clearly destroyed all these when she moved mountains to save Sasuke. Her only obsession to save him and bring him back, kind of annoyed everyone. It more or less sounded like, there is nothing more for her other than pining over Sasuke.
It was her love for him, that challenged the belief systems of Sasuke and turned him into a good person. Her feelings for him are more than infatuation and yet many people do not understand that. She’d fallen head over heels for Sasuke and strongly believed that he was a good person even after all the things he’s done against the village. This is one of the main reasons, many fans hate her for.
On her own, Sakura definitely takes the mantle of being one of the strongest ninja around. The problem is that she’s constantly overshadowed by the people around her, who are simply on another level of power altogether. This often makes her character a bit hopeless and dependent, which is hated by many fans.