Can we expect new gear like skis, snowshoes, and dogsleds for improved movement over the terrain? How is this going to affect day/light cycles, will there be areas affected by seasonal periods where it never really gets dark/light? This could all be really fun stuff that you don't often seen in traditional fantasy settings.
Somewhere we will need new equipment.
As for the light/day and stuff, I'm wrestling with that. It's important that I don't get caught up in making The Bitter Reach a climate simulation, but rather take on ideas like the one you suggest, to make it more "fantasy".
since we only have the broad strokes about the world itself nothing says it needs to be a globe, having a sun god mad at the northern reaches so his power is lessened, or the world is on the back of a tortoise so the north is on a sharp curve away from the sun, or we're on a ring world and the cooling systems are working overtime, or it just is cold... so many possibilities so little time.