even if sakura cannot fight as well, or have any unique abilities like everyone else...shes considered very clever and bright (i dont know if shes as bright as shikamaru) and like others said, she controls her chakra perfectly and knows how to make attack timings perfect without sharingan or byukigan.

besides, if she wasnt there, then narutos team would be kinda, lost and hectic, no?

as regard to her best move...her use of kawarami no jutsu and bunshin no jutsu both seem to be close, as she can devise clever ways of using them that others never saw (zaku and ino didnt see it coming)