Kishimoto never really knew how to make genjutsu work in fights eventually dropping it to just use for exposition dumps.
He should have given her wood release as it is one of the three great powers in Naruto: Eye powers, Tailed Beast, Wood release. Guess what the other two have?
The first Hokage was able to rival Madara with only wood release while he had both Sharingan and Kurama. Madara was only able to surpass Hashirama when he got wood release as well.
I'm not sure Wood Release is suitable for her. Maybe other elements but not Wood (unlike what the Boruto team did to Moegi out of the blue!) I cannot picture Sakura doing any Wood jutsus besides Yamato.
Or that. Just something that defines her, and only her!
How about a Jutsu that heals from afar? Strength of the healing depening on how strong her bond with that person is, or on trust. Or give her the ability to manipulate chakra. Could've been used to help Naruto to control the 9-Tails chakra. Would've made her pretty relevant and useful.
She dosen't need to be strong like the boys ... Her strength is supposed to be her smartness, right? Why not just go with that? Make her the reason for winning battles that seem lost. Kakashi is also smart. Why not let him train that side of her? The Potential is Endless.
See? That would be interesting. Healing from afar based on bonds or a some sort of shield/chakra armor? Ooooh, the ideas along with the abilities I have plan for her. (I need to write this down for my New Timeline series)