Almost exactly one year ago I made this very same thread:
Guarding the Healers
Basically the consensus was, people have no idea how threat is generated, what threat modifiers are, etc...
Mostly healers cry about thrash pulls, and trash will go for the healer even if you somehow managed to stack every threat reduction buff in game on him. However, regardless of guard, as soon as damage dealer or tank so much as sneezes on the mobs they will leave the healer alone.
For the most part:
- If everyone in the group is roughly at the same level of gear and skill guard is not needed at all.
- If a damage dealer is significantly better geared or skilled than the tank, guard him.
- If no one has any idea of what they are doing, by all means put the guard on the healer, it's going to be a disaster anyway...