DRK Living Dead is healer's nightmare.

[Launched]

So holmgang is basically a Living Dead without the debuff?
Hallowed ground not only does not have the debuff, but also negates all damage completely.

Sure, Holmgang is just Living Dead without the debuff if you ignore all the other things that make it unique. Holmgang lasts 4s less than Living Dead which is a pretty big difference. There are mechanics that PLD/DRK can completely ignore with their skills that WAR can't Two examples are Holy Scourge -> Chastening Heat in A12S, and the 2 times in O8S where God Kefka will do Ultimate Embrace -> Hyperdrive. Then there's the target requirement, where DRK/PLD can take things like O6S tornados by themselves. WAR might be able to take the first one, but the second is on the opposite side of the arena from the boss. The root is sometimes good and sometimes bad, and it means you usually have to choose between using it to survive a tankbuster or ignore a mechanic. The root also makes it the worst for dungeons.