People really need to stop emphasising the supposed risk of Holmgang. The chances of you dying are extremely low because you'll only ever use it on a tank buster. Any healer who isn't asleep should already be preparing to heal you since they know busters hurt. Yes, yes, there are dumb healers who don't pay attention, but that can be said of every job. The benefits of Holmgang far exceed any risk. A prime example of how absurdly powerful it is can be seen in Godka, where Warrior is the only tank who can invuln three out of five busters. It utterly trivializes one of Godka's mechanics.

Frankly, one could argue all four invulns need an even longer CD than they currently have—essentially making them a one use per fight outside maybe Ultimate. If nothing else, Holmgang needs to be 5min, especially not that you can use Equilibrium freely. That's a 20-30k (currently) heal. This allows WAR to literally Tetra themselves—something DRK and GUN have no answer for.