Snowcloak represents sort of a culmination of the lessons learned by the dungeon designers over the course of the last few patches. They've shifted between dangerously open areas in dungeons, allowing parties to pull the planet and risk flaming out without careful and precise cooldown management on the part of the tanks and healers, and hoping the DPS are optimized enough to kill the enemies before they kill the tank. On the other side of the spectrum, you have dungeons like, say Haukke Manor Hard, which features the most obnoxious segmented dungeon designs, forcing single group pulls for the front half of the dungeon. Snowcloak represents a happy medium, I feel, in the trash department.
As for the boss mechanics, they are unique, and involve some limited environmental interaction that is novel for its time, and, later, these ideas are refined in other ways. The first boss, Wandil, has a signature attack called Snowdrift. If a player is not in motion about three seconds after the cast bar finishes, then they'll get hit with a stacking Frozen debuff. Other attacks give Frozen debuffs as well, and if a player gets to four stacks, they'll get locked in a block of ice for ten seconds, which is miserable.
The second boss is likely the one you'll remember most from Snowcloak, because of its large health pool and unique way of punching through it. The Yeti doesn't appear to take a whole lot of damage, but what the tank needs to do is bait the conal AOE attack Frozen Mist toward the Spriggan adds that appear. This will turn them into a snowball. Subsequent Frozen Mists will increase the size of the snowball up to two more times from its smallest size. Save the large snowballs for when the Yeti starts casting Northerlies, and you'll cancel the cast and deal massive damage. All you need to do is hit the snowball once, and it'll go rolling into the Yeti.
The harrier heretic enemies will do a long-cast ability that will turn them in to a wyvern, making them more annoying to fight, with raid-wide damage. They can be stunned when the cast bar is up, to prevent them from transforming and making your life easier.
The final boss of Snowcloak is Fenrir, who will call down three icicles, whose behavior rotates between two different configurations. The first, all three will choose random line AOE directions and fly in those directions. The second configuration, only two of them will do this, and the third will remain in place while Fenrir is casting Lunar Cry. You need to move so that the icicle breaks Fenrir's line of sight to you, or you'll get a vulnerability up debuff, and be easy snack for his followup Ecliptic Bite.
