>>106071521Thing is, bloodbending was relatively new, and nobody besides the creepy lady and katara knew how to use it.
Katara didn’t even need a full moon to use it anyway, so i don’t think it has to do with power but with technicallity. The lady invented it, but Katara refined it.
Also, since it became illegal in Korra, we don’t really know how easy is for someone to learn bloodbending, or how dar it’s capabilities are.