So I just downloaded the game after eyeballing it for a while and I have to say, I've had a really fun time with it! I'm actually not usually that into business sims, but IM has been really fun so far. I'm still getting the hang of the game, and I had a thought for something I think would really improve the early game experience.
I think it would be great if you had more input in the audition system! Or at least your very first one, since those initial idols are going to carry you until you start learning the ropes. A boost to rarer idol drop rates for that initial audition could be a good idea, but I think something that would be really cool is letting you select what attributes you want to focus on for an audition. Want to make a cool-themed idol group? Audition for cool girls! Need some good dancers? Audition for girls with 'dance' as their highest attribute!
Having more agency (huehuehue) over the types of idols you get rather than just hoping and praying you get lucky would be really useful. I also think something like an optional tutorial to walk the player through the process of getting to release their first single would be great, just to make the game more friendly to newcomers.