Had a funny idea, had the artistic talent. But the lack of humour and bad pacing quickly made this boring. There were very noticeble moments of nothing happening. I wanna say the silence was loud, if that makes sense. And then the Korra bit at the end I totally don't get. I'm not sure what the joke was meant to be. I guess you just dislike Korra? If so, felt silly you'd put that in when you're just gonna bother the majority of Avatar fans. Because Korra's series is more popular than Aang's.
You lose a star each for: bad pacing, many potential jokes not used, letting everyone know you don't like Korra like we'd even care.
having said that, I'd like to see more Avatar movies from you.