Sure, perhaps the feature wasn’t/isn’t at the top of the priorities list, but it’s definitely on the list. Plexamp 3 isn’t even a year old yet, but take a look at the changelog to see how much it has been improved in that short time.
I understand your frustration, but Plexamp is a labour of love, developed in Plex employees’ spare time. Have a little bit of patience and trust that the people building it want to see it grow and improve, too.