Maybe the thing to try is have the controller talk to a business process model rather than executing the actions itself. If the business process model indicates that the model is being violated (for instance, a step in the business process is skipped), then the business process model can signal the error to the control, etc. The business process is then hidden by the controller. Might mean you will have to build a different controller for different apps that use the same business processes, but the business processes can be re-used. This might be part of the step that I feel is missing.