Similar to the fact that they had like a thousand faces to make, I think it might be because the face editor allowed such a wide variance in the faces you could create. If they had used a much more restrictive system, say one that gave you 5 face choices for each race, then they could have hand crafted each one to look nice, using more complex tools than the in game face editor. In this case I think visual appeal may have been the price for uniqueness.