Create a "Revision Record" and a "Milestone Archive" feature.

Create a "Revision Record" as part of the project.

It would show the sheet revisions per model. The current revision could be collected by Model Metrics or dbexport tasks or the Revit Clarity Client addin. Everytime a new revision is added to the project revisions it gets added the  Revision Record.

Once the current revision is added to a Sheet, That Sheet number and name is added to the Revision Record.

This would be displayed in a webpage like a schedule to show all the sheets revision history per RVT model for the clarity project. This record should be exported as a csv file to be included in the Milestone Archive zip feature.

Milestone Archive feature would be the same as the project backup feature but the Zip file name would include the revision date and revision description. The zip file would contain all the links needed to reproduce the sheets needed for that revision. The current state of the Revision Record in CSV format would be included in the zip.

This would provide the metrics to show when a milestone archive is required to be created. There could be a past due number of days to trigger an an alert to request a Milestone Archive. 

Part to the Milestone Archive feature could default the description from the collected revision description.