Try pulling an enemy off of a PLD that has freshly-used CoS on a pulled mob. The DoT pulls hate off the initial Provoke, and even a few Tomahawks/Shield Lobs. For Twin we had the OT PLD run in first, grab the adds/Twin, and MT would Provoke pull Twintania off. If the PLD used CoS, the WAR (me) had a hell of a time getting hate off while running into position, because the tick after Provoke/Toma would still pull hate away. That's why guides recommend you don't use CoS when fighting Garuda EX when trading Plumes.
The amount of aggro this ability pulls in the beginning of the fight is quite nice. And it does take at least some thought, given the scenarios I listed above. It can make tank swapping difficult if done at the wrong time.
