When paired with a White Mage, AST will use it as a mitigation (via the shielding effect of Nocturnal Sect) for group/raid-wide damage.
When paired with a Scholar, AST will use it as a regen (via the stance effect of Diurnal Sect) for generally the same reasons.
It hasn't worked that way for a very, very long time. You now get both effects regardless of your sect.
What are some uses for Collective Unconscious?
- mitigating the bigger blows where your group can stack.
- applying a relatively potent (and free) HoT to the group (or even to your tank if you're running an expert roulette or whatever)
"Soak damage by stacking" mechanics are obvious candidates for this skill.
It's important to note that as Wheel of Fortune is a HoT, you can increase its duration with Time Dilation and Celestial Opposition. You can use it to your advantage to stack HoTs on your tank or to solo heal through stuff that you normally couldn't.
It's also important to note that being stunned or knocked back interrupts its channeling so you can't use it for things like Ravana, Sophia or Zurvan Ultimates.