The Legend of Korra

Actually, if I remember correctly Korra never once performed Airbending until the last episode. In the Pro-Bending episode she started fighting like an Airbender, with fluid movements and the like, but I don't remember her ever actually Airbending. That's why she was so surprised that she did in the last episode. It's possible that the Bloodbending reversed the bending abilities in her (IE, she could Firebend, Earthbend, and Waterbend but couldn't Airbend, and it reversed). Don't ask me how that's possible, just theorizing.

Well, I was more attacking the idea that Airbending was complete deus ex. Yeah, the whole timing is awkward and off, but it's not like it was a central plot point for a decent amount of the season. But attempting Airbending, I was referring to the few times Korra actually tried to make Airbending happen. I am aware that she was only successful until that awk Bloodbending thing happened.

While I will agree with the first part, it doesn't change that people will and are wondering how it could do that, something that will probably never be explained (Just like Zuko's mom never was).

Well I think it's important to note that the creators do acknowledge that everyone wants to know what's up with Zuko's mom (see: last episode of ATLA, first episode of LoK) and to top it off Katara says it's a "fascinating" tale, therefore we "know" what happened to Zuko's mom. However, Zuko's mom can be swept under the rug indefinitely since it has no important ramifications on the story. Bloodbending's power on the other hand, while it's likely to be swept away anyways, it's a lot harder to ignore. I do agree that they need to address it, however I also agree that it'll probably never happen (but not like Zuko's mom though, that may eventually happen).