I think its a great shot! What I would do is crop a little of the bottom, maybe try 16:9 aspect ratio, so there is less "empty" space in the photo. You can also try using the rule of thirds to put focus points in corners and add leading lines. Basically, in this photo there is a lot of dark hill, and there could be more aurora lights
Did you use 2 sec timer and slow shutter NR? Beyond that, I think the main things to improve this shot would be to buy new gear
K-30/50 would give you better noise performance, so you could use ISO 1600 or 3200 without a problem. But this is hardly a critique, just a thought.
So I would say you are definitely on the right track! More PP, like taking two frames, one of sky, one of foreground, and one of city and then blending them together (HDR, tonemap style) might be a good next step, but that can quickly become a photoshop nightmare!