I know I'm very late to the party, but just came in to say I'm a huge fan and recently rewatched the entire series (and the original Avatar: The Last Airbender) and I love it so very much.
The finale was great, and culturally important. It's amazing that we're in 2015 we still have to take special note of a bisexual relationship on television, but kudos to the producers for taking that step on a kid's channel.