To anyone doing the "What about (character)?" joke;
Your comment is predictable, useless, and unfunny. Please, please, spend just a little more thought in a joke before posting.
Anyway, this question is pretty old. I don't think most people will have a problem. Protagonists in games, or anything for that matter, are usually straight, white/asian and male, because that's the target demographic. It would be relateable to more people, since the majority of the crowd will fall into at least one of those categories.
But, there are non-white and female heroes, too. What's different is that games are usually targeted at boys and young men. Y'know, those impressionable youngsters, who curdles the blood of his parents when he is exposed to things, like, the real world. Those kids that generously throw around the term "fag" and are often put off by a character who seems just a bit too effeminate. It would be a hard sell.
I can't really think of any games with gay protagonists, that aren't parodies. I wonder if Rockstar is planning to do a reversal with Gay Tony. But then again, it's Rockstar, so the main character might just be a construction worker who likes to talk about the YMCA, if not just outright divert it from gayness.