Well I'm not so sanguine about the amount and kinds of roles that "A or B" List blacks are getting in the mainstream films. Some of them aren't either. I'm also not sure that we can apply lettered list status so easily for blacks due to how they are treated or regarded in white Hollywood.
For many black actors, for example, that should be "A" List or might be A-List in the black community, they are barely known or register in the mainstream (i.e. white folks), so they take roles where they can get them, and some might misinterpret that as them taking roles beneath them or whatever (however I think the TV stigma has declined quite a bit over the last decade or two).
Despite Perry's flaws as a writer and director I do have to credit him with providing opportunities for a wide range of black actors and some brown ones too.
I do agree that Kim K. isn't the most talented person, however Perry has already pulled a coup by casting her. It will get people talking about the film and might even bring her audience, or fans, in to see the film if they aren't TP fans already.