I assume this is character wise and Hinata edges it for me if that's the case. Her backstory (low self esteem, no confidence, aversion to violence) especially in the setting she was written/created in was unique to me and in conjunction with her fight against Neji, it made her one of the characters that stood above the rest for me.
It seemed like nothing, but her remark to incite Neji at the end is not something that comes easy with a personality like hers. Absolutely not easy at all. That was extreme character development imo and i was looking forward to more as the manga progressed (same with Lee) but well.. Kishi.
I completed the Nue arc in the anime and Sumire's backstory has been reused many times in numerous media i've come across... and she really was just there character wise for me.