I was wondering, have you possibly considered expanding some of the marketing options into being a new part of single production, like making a PV/Music Video to promote the single? There’s already Bikini PV and Viral campaign that sort of hint at this, I could see that being it’s own category and being expanded to include different types of videos (Flash Mob, Traditional/Kimono, School, One-Take Dance, Drama, Action, Mini-Movie, Sports, Parody, Band PV, Retro, Travel/Foreign Location PV....)
Maybe these PVs could include a new staff role, or maybe you could “audition” Directors like you do with idols when you want to have a PV and chose from randomly drawn Directors with varying specialities/production levels in each type of PV? I could even see these PVs becoming a separate tab similar to media/part of the single release results screen where you can see how many views you got for the PV first week and see how views increase/decreased after the release week/week-to-week
Also, I don’t remember who said it, but I think being able to include more than one song on each single, and possibly work up to producing albums would be a cool addition. (You could designate which song is the A-side, but additionally package it with more songs that have different styles/idol lineups that can affect the appeal and sales of the entire single, maybe even solos, etc.) Each song might need separate production for the lyrics, dance, song, PVs so there’s a opportunity cost of being able to release less singles/having a more expensive single but it might have improved demographic appeal/sales. Also would give people with large idol rosters more to do with their girls instead of having to switch them out every single release