I think it's just the Zone system that makes it confusing and even unfair. Two cities in the same zone can be 1,000 miles apart (a guess but probably not far away) but earn the same miles to travel to/from DXB. This benefits the one closest to DXB as they are getting more bang for their bucks but the traveller from further away is losing out.

In my case, I fly ex GLA which is the furthest away from DXB in the Europe West Zone but someone flying from FRA gets the same miles while flying a much shorter distance.