I almost wish "Ma boy" had just been a Hyorin solo track. Bora is hardly on the track besides her ten second rap (which I'm sure Hyorin could've handled herself), and I'm sure Starship sidelining Dasom and, especially, Soyu might cause some strife within the group. Hyorin has basically been pushed as the star of the group since day one, so I think a solo digital single would have sat better with the other girls.
I may be wrong, but Soyu always comes across as craving the spotlight (and if she had been in almost any other girl group, she probably would've been the lead singer), so I can see this subunit eating her up inside, haha. but, maybe I'm wrong, and Soyu and Dasom will have their own subunit where Soyu can sing 98% of the lines.