Hi, I really love Plexamp and it quickly became my primary way to listen music. It made me also to finally organize my library. It took me a lot of time but in some cases the result is mediocre. Plex server apparently ignores a composer ID3 tag. It means I cannot search for example for Briten’s music by his name. To make a composer an album artist is not an option because often there are more pieces from different composers on one disc. I do not know whether there are more tags missing which other consider important but when there is now such a great reason to use plex for music this small step could make it even greater.
To make a long technical story short - it would not be very difficult for Plex to read more of these tags (composer, producer, conductor, remixer, lyricist etc) and display them but given the current database structure, it would be quite difficult to enable users to search or filter on them.
This is likely why Plex hasn’t added features like this in the past ten years, and probably will not do so unless they do a major rework of the underlying database and API.