I agree with Chris that the fundamental issue is that the image is drab. It's dark and has limited contrast. However, you don't need to get as fancy as luminosity masks to improve this. You can make a great deal of improvement with basic tonality tools, like levels or brightness to lighten the image and a curves adjustment to add contrast. I'll post below a very quick edit with just brightness and curves. I didn't take the time to get it the way I would want it; I just wanted to show the impact these basic tools can have.
Re Topaz: can't add anything, as I have never used any of their software.