The animation is pretty good and I like the character design, but I don't know if I'm impressed with the writing.
I like the direction the story is taking, but I'm not seeing much originality with the characters yet, or the dialogue. I'm hoping they make good on what they said about taking a more mature turn with the show. To tell the truth, I kind of wish it had gotten picked up by Adult Swim, rather than Nick.
I'm also kind of wondering about the steampunk angle. Where would the British influence have come from? And I hope they don't follow in the footsteps of X-Men. The premise has the potential to seem a bit washed out, considering all the X-Men movies/series' that have been spawned in the past decade.
Someone else said the villains seemed boring. I agree. The AtLA team has always spawned some pretty boring villains, sans Zuko and Azula. They like making the bosses super evil, which will probably be the low point of the show. I'm hoping they also veer away from making a romance present too soon. I'd rather see Korra single for a while.
I'm glad they aren't relying too heavily on The Legend of Aang. I just wish they'd tried to break their character molds a bit with the brothers. I'm seeing too much Zuko/Aang there. Tenzin being super serious is a nice surprise, though. And not hooking up the kids of the original gang, or even having them be best friends, is interesting.