Having leveled all the Trusts all the way to 80 they definitely have their break points.

Anything over 2 packs and both healers just stands there and lets you die. It's like they have no idea what to do when you're HP is dropping quickly. This is when I was a PLD with hallowed ground AND clemency. Still died multiple times.

The lack of AoE, even a 100 potency one, slows things down considerably.