I'd like to propose an overhaul for a feature that is very underutilized, collection feature. Instead of using collection as a mere filtering tool, I think it would be cool to see a tree-structured collection. This allows users to pool media that are related to each other. I said media not films or TV shows because it isn't section-wide but library-wide, allowing users to put movies, TV series, music or even pictures. Take a look at the mock-up I've put together and notice there is mixture of films and TV series with Marvel Cinematic Universe with Agents of S.H.I.E.L.D.
  
Collection Creation Settings mock-up
Above is settings mock when user creates the collection. The existing metadata editing capability still applies to the collection so user can choose/upload poster, background image and everything else. As for displaying the collection in the library, feature would allow users to choose two display options. "Collection Only" would be the tree-structure view where any media within the collection will not show outside of that collection. This will be fitting for movies such as Lord of the Rings trilogy or Harry Potter series. "Collection + Individual" would show media both within the collection and outside of collection. Marvel Cinematic Universe would be fitting example since technically not all movies are not directly linked together. They only share the universe but not necessarily sequels to the previous film. Additionally, say if you are on pre-play page for Fellowship of the Ring, it would list the collection it belongs to as well as other media that also belong to that collection. Something like the mock-up below.
Of course, collection's metadata can be edited just like any movie or TV show. Additionally, edit includes play order that will over-ride collection order if user wants to have collection list in certain way but play in a rather different order.
Not only will this overhaul be useful for movies with sequels but you can add printed bonus material that come with blu-ray/DVD or booklet that come with music album or add music videos from that album, allowing you to have all-in-one comprehensive experience. Also it would allow better and comprehensively organized anime library for anime lovers (anime franchises tend to expand its franchise through different forms of media (TV series, movie spin offs/sequels, radio shows, comic books, etc) which Plex cannot accommodate at current state.) I know that this sounds a bit like hybrid library idea (and that implementing hybrid library pose some technical challenges) but this collection idea would merely shows all the media in one place but points to the already existing media entries within the PMS when accessed, making it more of a alias or symlink of sort if you will. What do you guys think?
