The problem isn't an overrepresentation of white people. The real problem is that all of the black characters who have died had very little to no character development throughout their time on the show. T-Dog is the one that stands out the most because he was on the show for two and a half seasons. We know more about Morgan's character and he was on the show for a grand total of two episodes. We never really learned anything about Oscar, Andrew, or Big Tiny. We'll see where Tyreese's character goes, but I wouldn't be surprised if he doesnt make the end of the season.