I know the answer to this is probably going to be no.....
...but....
A standalone music player for iOS would be very useful. Trying to get the wife to use the full client for music is just not happening. Something that was simple and intuative and quick and easy to use would be killer, something like spotify.
The simpler the app is to use, the better.
If all else fails, I have a project that's on the back burner that was an iOS music player for subsonic, but I could always targ
Simple. Only music related options and nothing else, it doesn't matter how hidden the video player is or otherwise, it needs to not be there.
Take a look at Spotify, Apple Music, Tidal, PlexAmp, they're optimised for a workflow dedicated to play music, they all have give or take the same look, feel and workflow.
This is why my wife will use Plexamp and won't use Emby for playing music.