For Idol Manager I think it would be cool if we could have a survival show for rookies (and also for the ones that are not rookies). So it would boost their popularity and they would get some new skills.
Maybe if they are good enough they could also be promoting in a temporary group and with their own group (temporary groups like I.O.I and IZ*ONE)
For every episode they last we could also get a little bit of money? For example when your idol is against some other idol and you win you move to the next round, get new fans, gain a little bit of skill and you get paid some money.
Edit: also it would be cool if we could have contracts with idols like 7 years or something I don't like that idols are telling me when they want to graduate. Because then I can be prepared to train new idols better. When they say they're leaving in like idk 3 months I feel like I don't have enough time to train idols who are below average.
That's why it would also be cool if we had a category "rookies" who only train and wait for the debut.
Well these are just my ideas. I hope some of them are good enough to be added in the game one day.