I am only a game designer in theory

and didn't finish any game beside some rough prototypes, so be aware of this when reading my thoughts...
I would try to think like your target group. Analyze their playstyle, interview them about their favorite games in the genre, read customer reviews for management games at amazon and adapt to your target group like a good actor. Think as a management game lover. Then you may be able to figure out where they get the fun from and what the perfect management game is made of. After this you can modify the vision and innovate. Then interview genre lovers about your innovations and adjust them. Repeat this until you feel good with the game...
edit: Well, after thinking about your post, I guess you are already doing what I recommend by asking in this forum etc. I believe that game developer forums aren't that good for understanding other's fun in games, because many of us have visions of ideal games we want to make, while disconnecting from the average player. The need for innovation and creativity often even affects our way of seeing fun in games. While making "indie" games looking into indie game forums makes sense, but you should explore other communication hubs for other target groups. We as developers often can only share our observations.
My girlfriend loves time managment games (e.g. Cake Mania). I think she gets fun from recognizing patterns of action and timing in combination with the pleasure of upgrading and medium to fast paced action that requires some level of concentration (in a way that you can still listen to an audiobook but enough to distract you from the real world).