Unless I'm mistaken, this doesn't fulfill the requirement: > I want the ability to rate music across multiple user-configurable dimensions. Add tags. Create sm

Unless I'm mistaken, this doesn't fulfill the requirement: > I want the ability to rate music across multiple user-configurable dimensions. Add tags. Create smart playlists that interpolate between these. I'd actually pay for a 3rd party metadata service that doesn't actually provide the music at all, but just let's me tag and rate some across all music streaming services. I've even thought about building that (simply for myself to begin with). I want ratings, instrument tags, mood tags etc. Let me search for songs with 'piano + synth + dreamy + weird' instead of throwing some stupid recommendation my way. And use those tags to find similar tracks across genres and decades of time, instead of just saying "Nirvana and Pearl Jam must be the same because they're early 90s Seattle bands".