i red that Kishimoto wanted her to be a nobody, also she was probably created only for the love triangle crap his editor told him to do and he never really planned her entire background and evolution, stuff happened because the MC and his fav character changed so he had to change her too...
the fact that she became Tsunade student was only because both Sasuke and Naruto became students of 2 other legendary saniin, it's pretty obvious it was the only way to show a more grown up part 2 Sakura + the nex GEN saniin.
imo Sakura would have been more valuable with Kurenai as a teacher, also i'm pretty sure that Kishimoto didn't wanted to put Hinata in team 7 and destroyed her to begin with and maybe he had already planned the other teams enough to be satisfied so he simply did his best with this rickety character called Sakura.
tbh, when i saw Karin, it was like the missing parts of her character suddenly appeared, that's why Karin is more interesting than her for me :erm:
it doesn't mean he 100% hates her (even if it's clearly sadistic from him to use such a cliché character aka the shojo stupid tomboy pink haired girl, superficial/selfish/immature etc) i just think he was never interested to work more on her character and no he didn't do this with every females...
Sakura is not interesting because Kishimoto wanted her to be like this: basic :dunno: