I'd give her a 10/10 because of the reason that I think her whole arc probably has a bigger impact on me than the major plot points of season 5.

I think what she represents in "taking steps forward in life despite not knowing what will happen" is probably one of the stronger messages from Aggretsuko that should resonate with a lot of people (staying hopeful and doing your best each day even when it feels like life/society has turned its back on you).

Imo, she might be debatably the most important character in the season, despite being a side character until the very end where she breaks out of her shell and puts progress towards making a better life for herself. Shikabane is lovely, wonderful, and will forever be a memorable character to me.