Its not at all clear if she gained full control of the avatar state or not. Did her going into it really seem intentional? It is clear that she now can access it (something Aang could having only learned Air, as he's much more spiritual). Aang restored her bending pathways and unlocked energy bending for Korra akin to what the Sea turtle did to him.
The logistics of her air-bending don't make sense on its face, unless the chi pathways are all distinct in a way that Amon didn't blood bend her Air pathway simply because he couldn't detected it. I guess it could be argued that having all of her other pathways closed so suddenly, and then trying to bend, might have helped activate her air bending, but it was a little odd. It's pretty clear throughout the series that her inability to Airbend is psychological, as was her inability to be in touch with her spirituality. If Aang can suddenly spirit bend at such a level to take away another's powers, I don't think Korra suddenly being able to air bend under very complex circumstances is that big of an issue.
As an aside (and being on topic) Book 2 is apparently called
. I can't wait to see them explore more of that, since it was always engaging and also relatively under exposed in AtlA. This will also continue nicely from book 1 regardless of if she attained full control of the Avatar state or not, because of how the Avatar is effectively powerless when she has crossed over. Korra would be far less defenseless than Aang was, which opens up a lot of flexibility for Book 2.
The logistics of her air-bending don't make sense on its face, unless the chi pathways are all distinct in a way that Amon didn't blood bend her Air pathway simply because he couldn't detected it. I guess it could be argued that having all of her other pathways closed so suddenly, and then trying to bend, might have helped activate her air bending, but it was a little odd. It's pretty clear throughout the series that her inability to Airbend is psychological, as was her inability to be in touch with her spirituality. If Aang can suddenly spirit bend at such a level to take away another's powers, I don't think Korra suddenly being able to air bend under very complex circumstances is that big of an issue.
As an aside (and being on topic) Book 2 is apparently called
Spirit