I would like to make a few suggestions!
First of all, i think its a must to put albums in the game
second, i think you should be able to choose what to call your fans
i think it would also be cool to be able to schedule events for the idols, like a meet and greet or autograph signing, performing in festivals and small stuff like that
It would also be nice to have some more outfit choices lol
and the last suggestion i have is the ability to assign the idols roles like leader, main vocalist, main rapper, etc