Depends on the group, generally speaking though, from my own experience, it's a lot better to avoid as much of the AoEs as possible, as they hit significantly harder than the basic attacks from the mobs, just try to keep the mobs in the same spot if you can. The DPS and the Healer really shouldn't be getting hit, except by gliders in BL, which would be the point of stacking in order to let the healer if they are WHM use Cure III.