RPGs are pretty diverse, generally. You get heroes and supporting characters ranging in ages from children to the elderly of both genders. You get a myriad of settings--fantasy lands of magic and legend, futuristic galaxies with high technology and aliens, post-apocalyptic wastelands, modern-day Earth towns and countryside, floating sky islands, underworlds, gritty cyberpunk cities, and many more. You encounter all kinds of ideas, themes, and messages in the games' plots. You even see dozens of different expressions of art--a game can be cartoony like Paper Mario 2, realistic and dark like the Fallout series, obnoxiously colorful like Chrono Cross, so anime it hurts like the Tales of series, pleasantly simple and pale like Breath of Fire 4, and so on. You just plain find all kinds of stuff in RPGs.
It is thus somewhat surprising to me that the genre is extremely homogeneous as far as race goes. Fact of the matter is, the extreme majority of RPG characters, villains, and NPCs are Caucasians. You do see a few Asians, but that's about it. There are very, very few people with darker skin in these games, and those that do exist are found by and large in North American RPGs, like Fallout and Mass Effect. RPGs that come from Japan (which is to say, almost all RPGs) very, very rarely show any racial diversity. Heck, you get far more humanoids of fantasy races like dwarves and elves (all Caucasian ones, of course) than you do of regular humans with different skin color. I can quite literally off the top of my head think of more centaur party members I've seen in RPGs than I can black people.* And are there ANY Hispanic RPG characters at all? I'm certainly having trouble coming up with one.
The other problem with this issue is that, with the Japanese RPGs, the few characters of different races shown are often callously stereotypical. I mean, let's face it, even if he had some modestly okay character development, Barret in Final Fantasy 7 is a Mr. T knock-off. And Natan in Shadow Hearts 3 is about as generic a Native American as can be imagined, from what his limited and lackluster dialog would indicate.** And if they're not mildly offensive stereotypes, the ethnic characters are usually just mild and unimportant--Kiros from Final Fantasy 8's a sidekick of a side character who's most memorable for interpreting someone else's eye blinking, and General Hauser from Suikoden 2 takes the backseat to pretty much all of the other military leaders and strategists in the game, for examples.
Now, the simplest explanation for this is that Japan by and large has a homogeneous population. Pretty much everyone over there is either Asian or Caucasian; it's very rare to see a person of any other ethnicity (or so I'm told by my friend Jolt, who's the best expert on Japan I know). What exposure the Japanese media gives to people who are different also often reinforces stereotypes (again, from what I'm told by Jolt, although I've read some online articles about the subject that corroborate this). So the Japanese who create these RPGs most likely don't have much exposure to various ethnic groups, and what experience they do have with them may not be good for breaking stereotypes.
The problem I have with this excuse, though, is that Japanese RPGs by and large are still founded in Western ideas and culture. You get European ideas dominating the games' bestiaries, weapons and armor, locations and worlds' general looks, names, and character designs. There's a significant amount of Japanese culture mixed in, sure, and plenty of games are clearly inspired almost entirely by that, but by and large, the genre started with its foundations in Western myths and history, and regardless of how much it's branched out, it's still significantly based around ideas and implements of Western societies. So if they're looking to other cultures for ideas, they should be getting at least enough of a glimpse of them to have the idea to throw in a few more ethnically diverse characters.
Now, this isn't to say that Japan never does well with this, or even that North American RPGs always do. I may have criticized Suikoden 2 for Hauser's insignificant role, but the Suikoden series as a whole makes a solid effort to have some racial diversity--Suikoden 3 has several characters from the dark-skinned, tribal Grasslander clans join up with you--a few of which are significant and important characters, and one of which is actually one of the three protagonists (canonically THE protagonist, for that matter). That's certainly a step in the right direction. Final Fantasy Tactics has Rafa and Malak, who, if not terribly important characters, are still fairly significant and get decent characterization. Gallows from Wild Arms 3 is an excellent character whose Native American-based heritage works FOR his characterization, giving him a strong basis for his development (his attempts to escape his overbearing destiny as dictated by his culture, leading to his eventual acceptance of it) while not limiting him to some cheap stereotype--pretty much the exact opposite of one of my previous examples, Natan. And by contrast, Shadowrun SNES, which was made by an Australian game company and was based on a North American pen-and-paper RPG, contains a black character named Jangadance, who is a superstitious, pistol-toting, laid-back Jamaican, and a Native American character named Dances with Clams, who wears a headdress, seems to speak with deliberation, likes to talk about spirits, and basically looks like every Native American chief stereotype you've ever seen. That more or less counts as a Western RPG perpetuating stereotypes as badly as any Japanese RPG might, I reckon. Still, these are more or less just exceptions to a trend.
So yeah. RPGs are pretty varied in general, and their creators are more often than not making stories containing many elements founded in Western culture, so the racial inequality of RPG characters just seems odd to me. C'mon, RPG makers, stop letting The Man keep a brother down!***
* To be fair, almost all these centaurs come from Shining Force games, since RPGs in general stupidly don't have many centaurs, but even still.
** Shania, another Native American from the same game, doesn't set any records for originality, either, but with her it's more just her lacking any personality, stereotypical or not, so it doesn't count.
*** I apologize if this is offensive. I am whiter than a cotton swab dipped in vanilla icing left in the snow, so it's hard for me to gauge.