I hesitate to offer suggestions in the HDR Forum, because there are members here with more HDR experience than me, but I think you're onto something. The way you assertively burned the sky is something Ansel Adams used to do in his later years, and it provides some needed depth to the whole composition. (He also got roundly criticized for it, so watch out!) There are a couple of other spots I'd probably dodge/burn just a bit to help separate the visual layers, but that's just me.
Here's a thought derived from my personal experience. Sometimes when I've got a scene that I just can't get to pop, I'll reduce it to B&W and look at it from just a tonal perspective. I find that color often obscures things, and in B&W I'll see places where the image can be profitably tweaked. Then, armed with that into, I'll go back to the color image and try to bring those things out. Just a thought...worth what you paid for it.
[again, kudos for just getting out there in the cold!]
- Steve