why doesnt sakura develop or improve her shunshin no jutsu

[Tartarus]

She is just not in the league besides her strenght she is nothing even she isn't close to Sasuke and Naruto in every aspect.

90% of the cast aren't in Naruto and Sasuke's league. plus she was better at medical ninjutsu than all of the sand village. Saying she's useless is like saying medics and doctors in war are all useless :flaw:.