problem 1 : From a HR business perspective , Who requested /when  requested / why  requested .

problem 2 : When the business analysts have no coding background but can draw diagrams.

problem 3 : When you need to monitor the progress of work, perform between

             computer-controlled processes and human-controlled processes

problem 4 : A workflow engine is useful when you need to go from a start to a finish but there are many different paths/logic/rules .

problem 5 : Dont recompile , just change it runtime.