I feel like in a well written version of Legend of Korra, Vaatu would have been the ultimate antagonist in the finale and it would have ended with Korra learning to give up her Avatar powers to reunite him with Raava and achieve balance. Instead, he shows up out of nowhere in Season 2 and is forgotten about afterwards. Defeated like an evil to be destroyed rather than treated like half of a cosmic equation that needs solving.
It's the most 'ignorant westerner talking about Asian spirituality' way of writing a story about breaking balance and then 'fixing it' by leaving it broken still. Because we beat the bad guy, you see!
I am the stone that the builder refused
I am the visual, the inspiration
That made Lady sing the blues I'm the spark that makes your idea bright
The same spark that lights the dark
So that you can know your left from your right I am the ballot in your box, the bullet in the gun
The inner glow that lets you know to call your brother son
The story that just begun, the promise of what's to come
And I'ma remain a soldier 'til the war is won