I’m currently trying to understand your use case. The Rolling Stone‘s top 500 albums appear to be more of a static playlist (given there’s no metadata for RS rating/rank).
Just curious as I don’t really see the purpose of importing just the criteria…
As for static lists / references… there’s a few existing suggestions to allow importing playlists from various files.
  
  
    Once upon a time, a few years back, when our family first started using Plex, it was very simple to import an iTunes generated playlist into your Plex Media Server. Now it no longer seems to be a working feature. 
Sure, there are old instructions on how to add the proper Settings (Settings > Plugins) to point to the XML file for iTunes. But there is no option on the Playlist Tab of your Library to actually Import an iTunes Playlist, let alone any other playlist, as per some older instructions po…
   
 
  
  
    I would like to be able to export playlist information in case of server issues, then import them in the event of a failure. 
I have just had to reinstall my OS and Plex.  I had 78 playlists on the server, but no way to export them.  I had backed up the Plex Media Server folder in Users, but it had become corrupted due to my system crashing repeatedly due to a defective driver that was killing my server.  When I re-added the Plex Media Server folder I was able to see all my media and my playlist…
   
 
  
  
    It would be nice to have an option to point Plex to existing m3u playlists and use those for Plex playlists for a DLNA/UPnP music server or serving to Plex clients. Or if not to be used as Plex playlists it could be a separate feature called something like "External Playlists."  Right now I am aware of one piece of software that can make M3u available via UPnP, but I was hoping just to consolidate to use just Plex for all media serving.