A long time dream for me would be below:
Plex users who have access to multiple Plex libraries that have similar content should be able to browse all content from all libraries in a single view. Then when looking to play that content, it would play it from the preferred library (perhaps the local library, or the library owned by that plex user) if it exists first, or select a shared library if it didn’t exist locally.
If multiple libraries contain the content, the user should be able to set a quality target to play automatically. Eg: If Library X has 4K, but Library Y has 1080p only, it would play Library X automatically if 4K was the quality target, or it would play Library Y at 1080p if only 1080p was set as the quality target. If buffering or playback issues were detected, an option to flip to a different library could be prompted (Eg: it appears you are having issues from Library X. Do you want to try to play the content from Library Y instead?). Or even allow it to happen automatically (and even better, allow the client to select a preferred selection of libraries if multiple libraries are present).
Also, this would work way better if editions show properly as well.
