Finally! A developer-friendly solution for building Apache Oozie workflows: the Oozie plugin for Eclipse.
Although still an alpha version, it has great potential for being the first choice for developers for writing Oozie workflows.
Since the workflow is a graph, it is much more intuitive to edit it graphically.
Composing Oozie workflows becomes much simpler as it is a matter of: drag-and-drop, connecting lines between nodes, and filling properties sheet.
Development time is significantly reduced allowing much more dedication for logic rather than syntax giving a chance for writing more complex workflows and advanced use cases.
It becomes easier to read and maintain workflows. Everyone, including the less technical people, could become an expert at least in reading workflows.
As a plugin for Eclipse, it is well integrated with the developer environment. Workflow files are kept side by side with the orchestrated Hadoop jobs written in Java or Spark jobs written in, say, Scala that are in turn developed in the same IDE, Eclipse. That also facilitates the maintenance of all these resources in the same source control (e.g. the same GitHub repository).