the legend of korra is in one way or another better than the last airbender but y'all some "og is always better" head asses that won't admit it.
LoK dives into more complicated concepts that the last airbender ONLY dared to mention. LoK is set in a more modern time period making it's storyline relevant to today's current issues (especially in the first season)
bloodbending, metalbending, nonbenders and the restoration of airbenders across the world is something i always have in mind when watching the show, the show keeps you thinking and guessing how they could build a civilization of modern benders and nonbenders.
the storyline for their seasons AND episodes always keeps you entertained, it's fast, in your face, there's always something happening. which is important when making a series. something the last airbender achieved only until the start of book 3.
korra made such impact in the modern world of bending, taking life threatening risks and daring decisions. she became the START of the avatar cycle and brought union to the spirit world and real world, needless to say: iconic?
so yes, LoK IS better then the last airbender, know the facts, not always will the original be better than the sequel.
honorary mention is that the legend of korra wasn't canceled and forced to end because of "low ratings" or "bad critiques" it had mass viewership and was deared by fans by the time it was airing.
the series was forced to end because NICKELODEON thought it was getting to heavy and risky to air on the children entertainment platform.. now THAT is on TRUE anime -esque plot lines