Most characters look similar because people don't try hard enough to make the face of their character different from all the others. I have seen really good faces (even human male ones) in the game, because the player spent some time in the editor and used more than bust size to customize his character.
If you use nose bridge width, cheek size, jaw width etc. in combination you can make a lot of different faces. Have you noticed how much nostril height changes the look of a character? It's the small nuances that make the difference.
HEY! It's not my fault the default face (with minor tweaks) is the closest to my real one!