Eh, unnecessary. Besides, it probably would require much work. As far as I know, it only gets that information based on the file's resolution. If you were to put a WebDL file into your Plex scanner, based on the resolution it might show up as Blu-ray. Then you might say bring it in as a feature we could categorise it ourselves, which at that point would seem like a useless feature.
My opinion is my opinion, I'd like to hear other opinions.
It is unlikely, mostly because those are Scene Standards for encoding and distribution. They honestly have little relevance even there as each is a rather loose standard to begin with.
Was there more info you are looking for beyond the resolution & codecs used?
I would like to be able to see the bitrate, frame rate, audio frequency and codec. Some indication if the file is being direct played vs transcoded without logging into the plex server would be really nice for troubleshooting network issues and encoding methods.
On newer Rokus you can press the down button on the remote to bring this up. In the Android app, there is a "display information overlay" option to show this. In PHT, pressing "i" on the keyboard will bring up a bunch of info as well. I do not know about other apps. PHT provides the most info that I have seen.
I don't think indicating the source is necessary. We don't need to know if it's HDTV rip or BD rip, but I do think it'd be helpful if Plex simply shows bitrate which is more important when telling the quality of the file.