Ok I know this is probably wishful thinking and relies on a lot of things outside of Plex that probably won’t happen like availability of APIs but here goes.
It would be great if their was integration with the likes of NowTV, Amazon, Netflix and Spotify, YouTube etc so I can put my credentials for each into Plex and then Plex drags back shows, films and music available to me to become my one stop shop for all my media consumption needs - You click on the items and it shows you where you can watch/listen to it.
I have an Nvidia Shield and it kind of does this when an App has universal search compatibility - I can hit the search button on the remote, say Blade Runner and it shows me all the apps where I can watch it.