Music Boss was one of the apps Pebble users have found rather indispensible, and now there's a version for Android Wear. This is essentially an alternative way to control all your media apps (not just music) with swipe gestures and a prettier info screen. It's still not an ideal solution, but maybe you'll overlook its foibles.
The app on your phone is used to select the apps you want available in Music Boss. It supports nearly anything that can play video or audio like Plex, Google Play Music, Player FM, Netflix, and more. You can start Music Boss from the watch via voice or using the app shortcut. That gives you a card that you can use to access the app. From there, you'll use a double tap to bring up your previously selected list of media apps. Long-pressing on one of those opens it on the phone (neat) and a regular tap switches to that app in Music Boss.
Music Boss doesn't take over for your default playback controls on Wear – it's still an app that you need to explicitly open to use. This is far from ideal as you won't see any notifications on the watch while using Music Boss. If you go back to the home screen, you've got to navigate back to the Music Boss card, maybe going right past the default playback notification. On the plus side, Music Boss has left/right swipe controls for skipping tracks and the volume can be adjusted by swiping up and down. Pausing is as easy as tapping on the screen, and the progress bar from most apps is replicated in Music Boss.
Music Boss for Wear does some useful stuff, but it sort of butts up against the limitations imposed by Android Wear. If you want to give Music Boss a shot, it'll cost you $1.99. There's no trial, unfortunately.