When DocGen packages that were initiated by an Outbound Message fail to process, the only indication that there was a failure is an email that is sent to the User that the OB Message sends as, or in the event that the Drawloop Next formula field failed to specify a DocGen Package, no indication is provided and it will only be found by navigating to the document Queue.

It would be very helpful to update the failed record itself when there was an error.
This would allow us to leverage standard Salesforce reports and dashboards to monitor any automated processes and easily re-send any failed DGPs out once the issue with the particular record was resolved.

For example, I would set up an insert update that would update a "DocGen Status" picklist field to a value of 'Error' and a "DocGen Error Message" text field with the error message.
I could then create a report and dashboard showing any records for the object in question where the DocGen Status was Error.