idris' accent in the wire was shaky at best. in general, most people faking accents are not particularly good at them unless they are doing a strong accent that can allow for over acting.
but back on subject, hollywood has a tendency to give roles to one or two hot negroes at a time. 2013 was an aberration in terms of black people getting meaningful roles. they seem like they favor blacks from the UK, to be honest it will only be a handful and it will be a fad. black activity in mainstream movies is cyclical with a few male stalwarts like denzel and will smith as the exceptions. in other words, dont read much into it.