I miss the ability to tag the video in the client, When you start getting large library so it starts to get many movies.
IT happens that some movies are not in top quality, and when one says to you, the movie is not good and you should try to remember it in the memory may may be difficult.
I would like to be able to tag the film as, broken, Poor quality material or so.
As one can see from the server which films are marked as broken.
I was thinking of the star system to rate the file.
I tend to use features offered in Plex for other purposes than those they are normally used for like I add the series name to the director and the actors names on the credits for each episode of some special series (like daily shows with various guest stars) so I can do a search on them easily in the web application for instance.
So I would use the star system to define the quality of the movie (not the content but the file itself) if I were you and have a note somewhere to explain what the staring system means.