I get having the OVA feature Miya since she didn't appear that much in the anime, but that's pretty much the case for Team5th in general sans Akane so I would have rather seen something involving that group.

Since episode 13 gave screen time to Team6th and Team7th idols, Team5th is the only story they pretty much skipped over and expected you to listen to the drama CD for.

Idols but 17