Shamus, I think you're a great writer, and I've enjoyed reading you for a while, but I think you're really off base here. One of the issues is that games tend to have little room for "diverse" viewpoints, since they tend to show soldiers who are overwhelmingly white 20-30 something guys (with a moderate black population). http://news.yahoo.com/s/ap/20110308/ap_on_re_us/us_military_diversity .
The other reason is that most games are heavy action flicks. Women are slower, weaker and less durable than men, making them either unrealistically identical to men, or angering female gamers even more by being the "weak" option.
Well done games will use this to make the characters more interesting. I'll use the Resident Evil example. In the original Resident Evil, you could play as either Chris or Jill. Chris was stronger, more durable, and faster. Jill had lockpicks and more flexibility with her route. Both felt fun (Jill was the easier path by a bit), and it was a great game. Resident Evil 3 stayed with it. When you had to play as Carlos you were stronger and faster than Jill, but Jill was still the main character, even when Carlos clears out a route for her.
On the other hand, in RE5, Sheva's only distinguishing characteristic is that she's a black lefty (left-handed, I'm not going politics) that wears skimpy clothing. She is otherwise identical to the bruiser Chris, making the characters much less interesting.
Also, Persians are Caucasians too, Shamus. They may have on average different features, but their average skin coloration isn't much darker than the average American.