As a suggestion -- having the capability for metadata associated with some/all of the blocks could be helpful down the road. No matter how much sense a system makes to its creators, years from now the inheritors will invariably go "Huhh?" Not all that critical for symbology, but details, and especially standard details could benefit from a history that goes with them
Possibly something as simple as a matching XML document, with whatever information is deemed relevant -- creator, creation date, approved by, layering standard, client specific, etc.