Hi Steven, there are a couple of places you can add 'Notes' to your workflows: Right-click on the Workflow name in the Administration Tool and the Properties option allows you to define a Description. Descriptions are also available for a particular workflow state, and workflow transition (all via the Administration tool)
As far as an undo in the Card Editor is concerned, there is an Enhancement Request for this functionality: SPR 327259. I would encourage you to vote up that Enhancement via the SolidWorks Customer Portal. If you need help finding where to do that, let me know.
Finally, you can copy/paste individual states and transtions between worflows. Granted, you need to do it one object at a time, but it's generally easier than completely rebuilding from scratch.
Hope this helps.