This would be useful for situations where:
a) there is a formula error requiring you to update the template in Workflow Designer and relaunch a workflow without cancelling it altogether; or
b) a counterparty changes their mind about something so your metadata and draft are wrong. For example, a client just told me that group companies are in scope after all. It would be good to be able to go back to the Launch Form and change this so it updates the drafting, rather than having to manually input all the changes. Clearly this would overwrite any other changes made since launch.
The ability to change things in the launch form and relaunch would save a lot of time. I have not managed to use the "Start Over" option yet. I don't know how far back this takes you. Is it all the way to launch form or does it just regenerate the template based on the existing metadata? For some reason this option was not available to me in this latest example, despite the workflow in question having been launched after the Start Over option came out.