Im going to lean in the direction of the OP here, honestly. Looking at it in a vacuum its not a terrible burst heal, providing 20% health regen, and an additional 5% health regen and 12% healing recieved from associated passives and a 33% bonus when low health. However, if we look deeper, it gets a little muddy. In PVP, most players are using tri-pots or some form of potion that restores health which provides the 20% health regen buff with 100% uptime, most DKs use Volatile armor which provides the 12% healing buff. So really, all you get is 5% health regen on the bar that has coag (which is frequently the back bar), compounding the prolem is that many magicka DKs run vampire, which ruins any health regen bonus. So you effectively only get the heal from the skill; all other bonuses are redundant. Now compare the healing to a few other burst heals. Honor the dead has a equal or higher tooltip then coag, even with the full 33% bonus, and has a significant cost reduction built in to the skill. Sorc flappy heal is currently the highest tooltipping heal in the game and heals two targets for the full amount and comes with free (cost of 2 slots) LoS and (now terrible) damage. Warden heal is full AoE and provides 10% of both resource recoveries to caster and targets (along with minor toughness for 10% extra health). Necromancer heal either heals 2 targets or provides a significant resistance buff to the caster. Another substantial drawback compared to other heals is that you cannot use it to heal a group memeber (while some people may prefer the selfish heal, it is in my opinion, a drawback). I dont necessarily think the design of coag blood is bad. It just needs different secondary effects, slightly more raw healing power/higher low-health scaling, or a reduced cost to reflect the lower effectiveness of the skill compared to other class burst healing.