I personally would have preferred adult Chen's breasts to be a little smaller.
I get that the artist is driving home the point of sexy Onee-san Chen but those boobs are a little too much for me.
Everyone have preferences and I agree to these. I also do not get why the hair has to get super long with age. Ran is a mature and powerful yokai but she has hair no longer than to her shoulders. It is difficult to create the perfect adult Chen!