Hama discovered probably the most overpowered, deadly form of bending in the series. And then she proceeded to do absolutely nothing productive with it for over fifty years. No using it in the war effort, no attacking people who actually mattered. Nothing but randomly imprisoning Fire Nation civilians who don't have much to do with the war at all. Let's hope SV isn't that stupid.
The pitch: CN setting. Jack Spicer has been cast out of the Heylin Empire or was never invited in the first place. Feeling rejected (because he was), Jack Spicer decies to form his own evil empire from practically square one. Or square zero, since he isn’t that great a villain.