One of the things that drives me crazy in regards to using the "writing for another gender/ethnicity is hard!!" excuse is that, if your game is set in America, you don't have to stretch too far to write a character of a different ethnicity.
There seems to be this otherness that some people assume about minorities that makes them think it's going to be extremely difficult to write for a minority. American culture is American culture, regardless of your ethnicity. There are whites and asians that listen to Hip Hop, for example, and blacks and latinos who listen to rock and country. There are whites that grew up in ghettos that talk in slang, and there are blacks that grew up in middle class suburbs and talk in that dialect.
Living in a diverse city like Los Angeles for the past 18 years, I've met a whole lot of people from a whole lot of backgrounds. Some people are definitely migrants from other countries, but a whole damn lot of them are born and bred here in America, and have grown up in the same American culture that white people have. If you are writing a story set in America, I don't understand the whole bewilderment about how to "write for a black person," or "write for an asian or middle eastern person." When I sit down at my computer to write a character, and that character happens to be white, I don't whip out my episodes of Seinfeld or Friends to try and "get their vast and unique culture" down. I just write a character. Unless my minority characters are actually from another country, I don't beat myself over the head with nailing their dialect. From my experiences, Americans act like Americans, regardless of ethnicity. You don't have to untangle the mysteries of the black mind to write a black character. Just write the fucking character.
As I said a zillion times, I used to default to white characters 99.9% of the time when I'd sit down to draw and create new comics. I'm a black dude, but because the vast majority of the entertainment I consumed starred white males, that's who I'd create because, for millions of kids growing up in America, the white male is the defacto standard. When someone says "Doctor," "Lawyer," "Police Officer," "Astronaut," "Superhero," I guarantee that for millions of people, a white male pops into their head. If I say, "Thug," "Gangster," "Criminal," the vast majority of people will picture either a black or latino male. Those are the types of almost reflexive associations we make with words, so often, when a creator sits down to create, and he/she says, "I'm going to write about a police officer who gets mixed up in organized crime," they're going to picture a white male.
Once I realized how much I defaulted to the white male protagonist, it broadened my thinking, and I started asking myself, "Why does this character HAVE to be white?" The answer is almost always, "Well, they don't have to be," then the question moves on to, "What ethnicity should they be then?" and it opens up the door to create a character that is different and unique visually, as well as from whatever background I'm going to give them (Happy, Tragic, etc). I still create plenty of white characters in my stories and comics, but now they aren't the only characters I create.
Funny anecdote. I was riding on the bus one day, and I'm sitting in my seat, and these two tall, well built young black guys, wearing sports jersey's and shorts, come walking to the back of the bus. They're laughing and joking about something, and I'm listening to my music. Then, I catch snatches of their conversation, and they're talking about fucking Harry Potter, making jokes about Knight Bus and shit. It would have been so easy to characterize them as the stereotypical black youth, who's only interests lie in hip hop and basketball.
I've been a nerd my entire life. I've loved everything from Star Wars, to Doctor Who, to Dungeons and Dragons and comic books since I was kid. Been a gamer since '85, and haven't stopped yet. Many of my family and friends are exactly the same way. The shit we nerd out about and talk about when we hang out, or over Facebook, is no different than what people associate with white male nerds. Many of the women in my life (including my wife), are huge into video games and comic books as well. If someone were to describe my interests, you'd almost automatically assume I was a white boy, or maybe a Japanese Otaku. So why is it so hard for a white writer to write a minority character? Protip: It's not. That's not a good excuse. Whether you set your book in the suburbs or the ghetto, you'll probably have to do research anyway. That research will probably lead you to the conclusion that people in America don't really behave that differently from one another. Not enough to make it easier to just write them out of the story because you're too close minded to consider that your perspective and their perspective aren't that off from one another.
So no, I don't accept that as a reason to exclude creating minority characters as anything more than background dressing.