IMO if you're doing a body swap it's kind of a bare minimum to at least SHOW the characters before the swap has occurred, so that it actually means something.
Without that, like having the story start immediately afterwards without having seen them prior to that makes it feel a hell of a lot like we missed a scene. It also means we've not really established the male/female characters as male/female BEFORE they've become female/male, which kinda takes the fun out of it.
I get wanting to get to the exciting stuff quickly, but the setup part is kind of important.
@The Goat is Watching I get what you're saying for most originals, but this is a fan doujin of an existing work. The target audience are the fans of Shinym@s and of Asahi in particular, so there's no real need to introduce her and what she's like beforehand.
Base +6, Generic Anime Name +6, b911 -7, ensane +9
@koroko I just did a Google search and I'm not seeing anything about body swapping being a thing in Idolmaster.
So unless I missed some kinky stuff from the franchise in my internet search, I'm gonna say it still would have been a good idea to actually show the characters in the work before the swap so it wouldn't feel like a scene is missing.