In the third episode of Avatar: The Legend of Korra, we are shown a fragment where Lightning Bolt Zolt's bending powers are being slowly removed. What struck me was that, as his bending was taken, his lightning slowly became a flame and then fizzled into nothing.

The theme of impotency is very strong in The Legend of Korra. Non-benders not being able to compare with benders. Benders' powers being taken from them. Equalists not being allowed to practice chi blocking. However, I've never heard of benders comparing each others' potency before. It's like the Firelord and your average firebender has the same theoretical genetic potential.

Is it like that...? Can all firebenders use lightning with the right training...? Can all earthbenders use metal with the right training...?

We know one thing; Yakone and his family had a unique seemingly genetic quality to be able to bloodbend without moving and without a full moon. Did Yakone just happen to have the perfect training schedule...? We also heard in ATLA that not all waterbenders can heal. Is this a matter of genetic potential...?

Could it be that there are benders who are, in fact, weaker than the average bender...? Firebenders who can only light a candle...? Earthbenders who can only move pebbles...? Waterbenders who can only move droplets of water...?