X-Ray is amazing if you have not used it for your Desktop Maps... you are missing out.
Anyways my idea is a tool like 'X-Ray for ArcMap', which analyzes the cartographic contents of all the maps and services you have placed on an ArcGIS Online Map/App. I want to be able to follow the lineage chain of data from the App to the Map to the Server to the MXD and see where cartographic changes or manipulations were made on the dataset. (Ex: Max viewing scale or Transparencies.)