It'd be great if the TV app* would display the current track playing and album artwork, etc. when a device on the network is playing music. This would mimic functionality of the Android and desktop apps.
It looks like your idea was posted a while ago but, unfortunately, it hasn't gathered the minimum amount of votes to stay active in the Ideas Exchange (50 votes in the first 3 months). I'll mark your idea as "Closed - Not Enough Votes". You can learn more on how the Ideas Exchange works here.