A GUI is highly desired to manipulate workflow XML. This jira is tracking mocks for such a GUI.
I've created a mock and would request feedback from the community for the same. I referred <http://www.bpmn.org/#tabs-quickguide> for the notations, but have taken the liberty to simplify it.
PS: I'm a newbie to Oozie dev, so please pardon my ignorance of formalities