What he's saying, for those that can't read is "layer zones" is a fancy way of saying instanced. If they made Salvage so that you can enter solo, instead of going in with 3 or 4 ppl in 1 instance, you have 1 person in 1 instance, 4 times. So having 100 instances with 1 person in each instance, vs 25 instances with 4 people in each is a vast difference in server powah.