>>5872682ATLA was better I'd say. During their adventures Aang is forced to grow both as a bender and as a person. In fact, damn near every character has to learn over the course of the series. Katara learns strength and forgiveness. Zuko learns to follow his own path to redemption rather than that of his father's. Sokka learns to live with being mostly useless.
In Korra, we learn that if your master tells you not to play games and try to learn to bend, you should tell him to screw off and do it anyway because it'll teach you better than he ever could. The hardest thing Korra endures only lasts a couple episodes at the end of the first season. Instead of embarking on an adventure to become a better, more spiritual person, she only has to spend a small amount of time depressed. The wasted potential is ridiculous. They'd rather focus on kiddy stuff.