I watched the entire series of Avatar: The Last Air Bender this past week.
I'm pretty amazed at how fully developed the world seemed. It really felt like the creators had the series mapped out before starting. There were course-correction during the run, but that's understandable. I particularly like how they portrayed the Zyko character during Book 1. Starting that character with the background being slowly revealed was a good choice. I mean, you knew that something was up with his scar, but they didn't explicitly explain it until much later.
I understand that the show is made for kids, but some of the character's motivation/action seem imensely dumb. Example: The Dai Li (Earth Kingdom Cultural Guards) 's betrayal made no sense at all. I can't see any justification where they would join Fire Kingdom. Yeah, I get that they weren't loyal to the King, but to the Cultural Minister who was trying to overthrow the government. Siding with the enemy and then letting them take over... ugh.
Throughout the series (especially book 3), they constantly remind us of Sozen's Comet... but the heroes' constant dicking around really crushed the sense of urgency. A more productive use of the time would be to (maybe) destroy the fire kingdom's airships? Speaking of which, they could all have been so easily destroyed by Angggg... and if they did that, then Sozen's Comet would have been wasted. All of the fire/earth/water/wind bending could have been put in much better use. I mean, when water can be used to cut down a huge metal girder (as seen in the battle at the wall of Ba Sing Se), the water tribes should have sent a single water bender commando to destroy the entire navy. The person could just be hiding deep underwater, using water to maneuver, and then start cutting up the bottom of the ships.
By the way, I'm not so sure that a 12 (112) year old boy and a 14 year old girl should be able to comprehend love like that. Underaged sex. Ew.