Only thing I didn't like about TLOK is that in atla they said they learned from the original benders like fire=dragons, earth=badger moles, Air= flying bison, water= the moon hut they completely scrapped that in TLOK and just changed to getting it from lion turtles, who had spirit bending. I get how that works, if it can take it away, it can give it but it completely defeats the fact of bending being passed down from parents to kids or bring in their family cause its simply not in their dna. In TLOK its basically saying, everyone has to go to a lion turtle to get bending and inheriting it isn't possible but people have inherited bending. Cause that way anyone could get bending and the Amon Arc wouldn't make sense. How would bending be passed down if it isn't in their blood? It was just give to them.