I think I was too hasty in deciding I disliked Legend of Korra based on weaker writing. I did some thinking and remembered a technique I use myself later on in Naomi's Story: if there is an obvious villain, that opens up more space within a shorter time frame to have more good vs. good or gray vs. gray conflict among the "good" characters, and more evil vs. evil and dark gray vs. dark gray between the "bad" characters. As it stands in Legend of Korra, a rather large conflict between what's-her-name, Mako, and Korra is being set up, and Mako's behavior hints, at least to me, that the outcome of this love triangle is not going to be as simple as it seems. Also, I don't think Tarlok is going to give up because he lost his bending. Based on his personality so far, and how much he did without his bending, he's got more tricks up his sleeves.
That said, and some of my faith in this show restored, I still find it kind of funny that Legend of Korra is supposed to be darker than Last Airbender, unless the ending turns out more bleak than I'm expecting.