In Aang's defense, he went trough quite some too. I think you are trivializing the fact that he lost everything and everyone he ever cared for when he was frozen. He woke up to a world that had been at war for 100 years, where is entire civilization had been wiped out and where virtually nobody cared for or believed in the avatar. He had to learn how to bend 3 additional elements in one year without even a clue as to where a master could be found to teach him. He also got wrecked (maby killed) by Azula in Ba sing se and had to recover for a while too.
Honestly, I think that comparing Aang with Korra doesn't do right to both characters. We chronologically followed Aang for just over a year in the series, but followed Korra for multiple years. They dealt with their problems during different phases in their lifetime and had very different variables. Korra grew up in a world that was pretty much in balance, and Aang had to deal with the sh*tstorm Roku left behind with 100 years of war to settle, in a year.