Every character has there purpose in the story, if Kizuki purpose is to be a throw-away Villain at least she's making an important female villain grow and develop, I wouldn't say Horikoshi is bad at writing female characters, it's just a lot of them aren't important characters, a lot of male and female characters haven't gotten that much development in the cast mainly because the screen time is mainly focused on the Deku, Todoroki, and Bakugo
Right now he is giving Toga more shine then most of the other characters in the league, when he gives a side character their time to shine it's usually good