I'd really like to see a complex financial model which really allows you to explore different ways of running your hospital.
* Being able to meet pharmaceutical reps and negotiate drug prices
* Designing and building car parks and deciding what parking charges are brought in
* Adding a restaurant/cafe for staff and visitors
* Deciding when and whether to charge to treat patients that don't have adequate insurance.

These are just a few ideas, I have many more for other aspects of the game.