I don’t know if this is a planned feature or not but a common use case we have is for digital asset management and one of the core components of this is the ability to annotate and add comments to attachments.
Airtable has this in a basic form and it is enough for most clients so would be great to see something similar here.
On a similar topic it would be great if we could get preview thumbnails for non-image documents (docx, pdf, etc.)