That's still infinitely better than no female main character at all. Which is what we'd get, if we went "oh but this girl hero is just a copy of a boy hero so she can't happen, nevermind let's cancel it", which means there wouldn't be the potential success of the girlhero-following-a-boyhero as an encouraging precedent for an actual original-series girlhero, and people could keep whining "but there's a reason there's so little female heroes, it's because no one watches them !"

I'm not saying brykke are genderblind or magically all-feminist and aang just only happened to be a boy because they flipped a coin (though far as we know, it could have happened because yes, boys are just about one half of the world out here and it's not automatically evil to go with a non-girl, especially with he'd been incarnated as a woman before) -- but complaining of gender fail in this? God, so many other places to look first. How about all those other hundreds of action series where the women aren't even good, engaging sidekicks?

They said themselves they weren't interested in revisiting Aang. I seriously doubt she's going to be Aang with boobs. The setting is going to be different, even the universe surrounding them has evolved. It's not "the genderflipped gAang's adventures". Likely there will be themes in common because they're the same authors, but it just so happens I liked a lot of the themes I saw in the first run. The rest I don't care about. Avatar is a fascinating universe and usually has good character building, and I'm not going to complain that she wasn't the hero of the first run, because she's the hero of the second, and for all we know it could be even better than the first.