Plex as the associated app for Android Wear's "Play Music"?
The ability to use a Plex wear app as the associated music player on Android Wear devices would be perfect.
Currently there are VERY FEW apps that can be configured to be the associated "Play music" voice command app.
If I could request ONE new feature, this would be it.
(Well, this and including wear-remote app/functionality, but that's already been mentioned elsewhere on the "Plex for Android" forums. ;-p)