If you have WFA 2.0 installed, please click on Help -> Reference Manual. All the workflows and individual components of a workflow (like Commands, Filters, Finders, etc.) are self-documenting in the WFA Reference Manual, even the ones that you as a Designer build. Pretty slick stuff.
Oh, and another valuable piece of information documented in the Reference Manual is the workflow ID number. That number can be useful for Web Services calls to WFA for remotely executing workflows or checking the status of workflow executions without using the built-in web portal.
It also documents the returned parameters from each workflow that a system could query after a workflow completes via web services, too. For example, the canned workflow, "Move a Cluster-Mode Volume" has return parameters for DestinationAggregateName and DestinationNodeName.