I was re-watching Avatar: The Last Airbender recently and I thought a RP in it would be nice. However, there was the stumbling block of having an Avatar in the RP, as whoever was the Avatar would be incredibly OP. My solution was for the RP to be set a few years before Aang returned, to have it take place in the final years of the Hundred Year War.
Of course, the characters wouldn't be world-beaters who eventually went on to win the war individually, so the RP would be as much about story as it would be about character development.

Anyone interested?