The fact that so many firebenders can now use lightning in Korra is in and of itself bullshit. There were a grand total of 2 (maybe 3) firebenders capable of using lightning in Aang's time because it was so difficult to use and required apparently superhuman levels of focus. It wasn't some new technique that once found could just be taught to everyone, it was a known quantity that was simply nearly impossible to pull off.

Now it's so common an ability that entire swathes of people make 9 to 5 careers out of it. Bullshit.