I'm also curious to how the actual summoning process will take place, as in the animation. They could do something similiar to XI, large magic circle appears on the ground, your avatar pops up from that.

Though with the whole 'world changing color' effect and the areas being broken up into smaller areas, I wonder if they would cause everyone's screen thats in the area to turn to a generic CS of the arrival of the Primal. Optional to skip, of course.