Thanks for the suggestion! Makes sense. I went ahead and added it. It will be available in a future release.
Note: I added _CLIENTPROCESSFLOWNAME (NAME, rather than LABEL), since that is the more common way we refer to process flows. We used LABEL in _CLIENTTASKLABEL, since "task name" could cause some confusion with a task name (ex. "List Data task") versus the label for an instance of that task.