There needs to be a way to step into macro a which is component of parent workflow for debugging.
Currently the only way to achieve to debug these is to capture the inputs to the macro from the parent workflow, and then run the amend inputs on the macro. For iterative / batch macros, there is no option to debug at all. This can be tedious, especially if there are a number of inputs, large amounts of data, or you are have nested macros.
There should be an option on the tool representing the macro in the parent workflow to trigger a Debug when running the workflow, this would result in the same behavior when choosing 'Debug' from the interface panel in the macro itself: a new 'debug' workflow is created with the inputs received from the parent workflow.
On iterative / batch macros, which iteration / control parameter value the debug will be triggered on should be required. So if a macro returns an error on the 3 iteration, then the user ticks 'Debug' and Iteration = 3. If it doesn't reach the 3rd iteration, then no debug workflow is created.