I thought the vocal sounded nice. Good singing. I think it could be compressed a little harder. Ends of lines get lost in the instruments. I thought the harmony vocals were nice. I think you could nudge them up just a little bit.
I thought the rhythm guitars were too dark. Missing some hi midrange. They sounded like amp sims - lacking a bit of punch.
Kick and snare sounded pretty good. Cymbals sound a bit cheap, and I agree they're panned too hard.
This is one of my favorite Christmas songs. I think it's beautiful.