Oh yeah. That's why this film is absolute ****, because Toph isn't in it. I forgot about that... I hate watching the first series.
I thought Shyamalan was filming all three in one go to stop the whole puberty thing. It happened in the series and that was funny enough. Wikipedia however says he was writing the second during production of the first--BOO!!
When will another trailer come out? November-ish, maybe Christmas do you think? The tone of the film looks constantly serious which, especially with Aang, it isn't supposed to be.
Hopefully they'll show the entirety of the film by releasing 20 trailers like Half-Blood Prince, then I won't have to wait until next year for it.