Little late to the party, but uh... if your up to date on Korra, Korra is far stronger than Aang ever was xD
Korra can deflect a beam of spiritual energy for crying out loud. Season 3 finale she was bending far better than Aang ever did (even as she was poisoned) just by seeing it and its power. All you really gotta do at this point is WATCH LoK and its pretty obvious Korra is significantly more powerful within her respected time-frame. If it came to a 1 on 1 (which is fukin stupid) then no one would win. Since they all have the same elements, they can't counter each other well enough, and it would just be an endless duel of evasion to see who wears out quicker in the end, whereas the Avatar gets his/her strength naturally by having counters to normal benders, as they have every type of it!