I would be okay with extreme cold giving a movement speed penalty to zombies and juju zombies specificallyStill going through the quest, but the effect 'Extreme Cold Weather' probably shouldn't hurt you in undead form...since you know you don't have a body to keep warm per the description of the stacking dot.
Overall the quest was pretty nice with some new mobs and atmosphere. I would say the first part getting to the cave felt much more flushed out where the cave was rather empty, although the tunnel to the boss left that you know whats coming feeling which was pretty good. Biggest letdown was looting the named ring with will saves and poison resistance.