Other ideas and use-cases for a Document are documented here, we did some thinking on this in the past: Define the Document Asset - Google Docs
Also somewhat related is the idea for an Imagery asset (map layers): Imagery asset - any interest?
I did further investigation into this as well but having trouble finding where I documented the results… but overall I have some reservations about creating general document assets. Again, it really seems like this is a distinct concept from on-farm assets. They certainly need to be associated with assets and logs but perhaps there is a better way to design all of this. The request for a “document center” really illustrates this to me and how that experience is quite different than how you would manage other types of assets.
One thing I do remember finding is that we have an inconsistency between how images and files are handled. Currently only files can have an additional text/description associated with them. Images do not have this capability because the image reference field simply does not include the option. The ability to add some simple metadata for each uploaded file seems quite important. A document asset would not necessarily solve this issue, especially considering “a document” could have multiple files/images uploaded. This has led me to believe it would be best to replace all file + image references to use some kind of a wrapper entity that illustrates this concept of “documents” or “media” more generally.
Naturally, this makes the Drupal core Media module look quite appealing. Out of the box there are a lot of features this could provide, an important one being that each type of media could have separate bundle fields to store metadata specific to that type of media. It is also likely that we would get various UI features like the Media browser “for free”. The biggest issue I remember (and it is significant) is that the permissions associated with media entities are quite complicated and they very much default to being public.