Bish, I have to be honest and say that while I agree with you that there needs to be some thought applied to how representative the characters in entertainment are, this particular instance is not a good battle to pick.
At Christmas I was watching TV with my family and an ad came on for a new Aussie drama -series about a family and their inner-circle. My brother quite rightly pointed out that every single person in the show was white, the family themselves as well as all of their acquaintances. That made the show seem like something from, if not another planet, at the very least a very different time. On Christmas eve we had people over as we usually do, and the house was filled with people of all races and religions, as it usually is at those times. It actually feels really weird typing that because it's just how it is for me, so explicitly saying it feels really awkward. The point I'm getting at is that, as a White Anglo-Celtic Catholic person living in Australia my experience of the world is by no means that it is a predominately white place, so equal representation makes complete sense to me.
However.
In this particular instance it's a long-running series with an established cast of characters. The characters have particular significance to the fans, something Capcom understand totally considering the big fuss they made about being able to play both Leon and Chris in the same game FOR THE FIRST TIME EVAR, which honestly just made me think of Malibu Stacy's new hat but that's a topic for another thread. In that context, though, I can understand why adding new major characters for the sake of more accurately representing the racially diverse world we inhabit wouldn't have necessarily occurred to Capcom, or wouldn't have seemed appropriate.
Lastly, I'd be extremely surprised given what I recall from RE5 if there weren't a number of Chinese characters in the game who play major roles. It might be unfortunate that we can only choose between playing as a mildly effeminate or steroid-abusing white male, but progress takes time.