I really wish it stacked since Slow is kind of the only stackable CC there is the game as far as I know. Crowd Control is very weird in general tho because it sees almost no use. I never see Black Mages putting anything to sleep or Ninjas wasting a Jutsu to bind an enemy in place for 15 seconds. I really wish they let the CC abilities shine a bit more. If there were actual hazards we could push enemies into that would be nice. Might make Fluid Aura feel more useful. So many classes have skills that have zero use right now.