I have various conversations about art and whatnot with my friends who are in the similar field. Nicky O'Byrne in particular. We have both decided that majority of our people end up looking the same. Caucasian, young and fairly good looking. For me I can trace this back to my first attempts at drawing: which was copying from comic books. (Pre-Jim Lee, Essential X-men sort of stuff.)
Now I'm not blaming comic books, I love them too much. But I do get used to a particular way of drawing and/or making art. And I get lazy and repeat stuff I already know and am familiar with rather than trying new and possibly bad things.
So these are some attempts for the new and unfamiliar.