Diversity in Games

Off the top of my head, I can only think of three gay video game characters. The first is the mayor's boyfriend in Grand Theft Auto IV. He is particularly flamboyant but as you complete his missions he grows loyal to Niko and rewards him with a nice new car for his troubles. Knowing GTA, this gay portrayal was most likely a satire on political figures keeping up certain appearances in the public eye. The boyfriend as a character isn't too groundbreaking, mostly an archetype to fill the quota of the usually outlandish cast.
The other two are Colonel Volgin and his boyfriend Raikov from Metal Gear Solid 3. This relationship isn't explored too fully. Its mostly the groundwork for a joke where Volgin grabs Snake's crotch if he is disguised as Raikov. It's possible that Kojima created Raikov as a response to fan's backlash of the character Raiden since they look almost identical. He takes their complaints of Raiden's effeminate nature and over plays it in the outright homosexual character of Raikov.
The inability to name a substantial gay character in games off the top of my head just tells me that homosexuality is still a taboo most developers aren't willing to address yet. They exist in other media but sometimes are portrayed far too stereotypically. Comic books in particular have fully embraced gay characters, making such events as the coming out of Green Lantern and gay marriages borderline publicity stunts. Overall this implies that the LGBT community is a portrayal to gradually integrate into mass media.