No, she isn't. Aang pretty much had all four elements mastered down and pat by the age of twelve (or was it fourteen?). Korra on the other hand, just finished fire-bending, and has yet to even air-bend. Aang stopped an entire war, while Korra is struggling to clear the city of non-benders . Remember how Aang had trouble with earth-bending? He did his first real earth-bend a day or two after Toph taught him. Korra has been training for air-bending there for several weeks (I want to say three. Or is it two? Either way, she should at least be able to make a little wind poot or something). Aang has arrows (not really serious, but you have to admit that they're cool). Aang mastered the avatar state at either twelve or fourteen. Korra has yet to enter the Avatar state.
Its not that I don't like Korra (she's pretty kick-a**), but Aang is just...yes.