Considering the absurd block rate of Ochain, this ability isn't terribly impressive.
Yeah not everyone has an Ochain but it's not that hard to get either.
However didn't the update notes also say something about negating enmity loss while it's up? Has anyone tried tanking with it up vs say an Ukon WAR, or anything really that will give a well-geared PLD a run for their money (without Sentinel up obviously)