A few things I want to add.
*Since there's characters with age number in the game, how about prohibit/ not allowed girls under the age of 18 from partaking any sexy activities or business proposal as this shouldn't be happening realistically.
If this happen, this can result in an instant scandal that could potentially ruined the company such as reduction in sale by 50% or popularity.
This can only occur a certain amount of time like scandals act as warning, after three strike the game is over (such as government official shuts the idol group down due to multiple violation of the law).
That way, the game would be more harder and we have to pay attention to the girls age before assigning them to business proposal that they shouldn't do.
*Having an option whether to be causal in the workplace in business policies, (such as the employees doesn't need to be formal such as no need to say Mr. x
and can just say the player name instead casually) This boost mental points or morale. Or a formal workplace which boost quality.
*Notification sound for completion of task or activities being assigned such and setting to customized which notification we would like to have in the game. Same with business proposal being successful and available to accept
*Add the option to release a single as a standalone CD without anything included (A single album with no photocard, no handshake event no promotion included etc but the downside is risk of lower sale due to lack of marketing).
*Add a rare business proposal where the idol group get to perform at special events such as award ceremony or sports event as special guest. This result in huge rewards but bigger risk.
*New game in sandbox mode which allow players to skip the entire storyline and play casually without the main story just like the current beta state. (But requires the main game to be completed first).
Optional but too time consuming
*Add some dialogue for the manager to make the conversation a little more smooth, for example after the player choose this option:
Idol: Hi, you wanted to see me?
Manager: Yes, it's about what you said to x.
Idol: Oh, it's regarding the conversion I had with x.
Manager: Yep. I just wanted to let you know that this is all a big misunderstanding and I just want to clarify that we were just discussing about her future at x.
*Increase Starting funds by $2,000,000 on normal difficulty to make it a bit more easier for newer players.