People act like layering is some permanent feature.
That takes a heavy amount of coordination on both sides. If someone can actually coordinate a hundred people in the same guild who are all busy leveling and spread out across the world into a battle that big, they can easily coordinate 3 people on each side from the same layer to invite everyone into their raid groups to get everyone on the same side. Not that I see this happening in the first few week when everyone is busy leveling.