True. At the beginning she was that little fangirl, lol, but as time passed, she started to grow. She represents the normal human being. Does stupid things, regrets, cries, comes back, rises, fells sorry for it, continue working hard.
However, Sakura's had her own skills ever since the beginnings. She didn't had any special powers, but let's not forget she's the booby traps specialist.
In Forest of Death she prepared a trap for the others and actually showed great physical prowess ever since that when she had to carry that big piece of wood. And she was fairly skinny and had 12 years.
Also, she is a good deceiver. Hell, she took out by deceiving 4 Konoha rookies. Even Kakashi was impressed with her.
Personality wise she can be disliked or whatever, but ninja-wise she has her own merits, even if people downplay her.
Yes, she is pretty hated. That is one of the reason she became one of my favorites, because of the hate towards her.
Actually, there is a great truth you said there, the hate towards her come from the whole pairing/shipping wars. I never could understand that. Probably because I am ok with any ship? :|
Well, at that time of course it wasn't used effectively because Kakashi wasn't sure about the dimension.
However feat-wise she was the one who discovered Obito's jutsu first.
As for development, I am sure she will never become to OP because Sakura represents another thing in this manga.
For OP-ness we have Naruto and Sasuke and others.
But that's another thing.