I'd throw Nate Parker's name into the hat.
33 years old but frankly he looks like he could play younger if necessary (Of course, the longer Marvel sits on it's ass, the older he and everyone else being talked about is going to get). Good looks (No homo...but he has that square jaw look that comics tend to have). Great build and can bulk up more if necessary. He's not a star, but frankly, Holly-wood doesn't really have any
young black male stars at the moment and this SHOULD be the role that takes someone to the next level.
The truth is that these big roles in these types of movies usually audition everyone and their mother for the part. I remember "Girl With The Dragon Tattoo" had every white bytch alive going in for an audition. I'd imagine that if Marvel was truly casting for a Black Panther movie, you'd have every black male actor in Holly-wood lining up for a shot. This could do for a young buck what Independence Day did for Will Smith.
Only way that wouldn't happen would be if Marvel was dead set on some big name like Denzel or someone like that, but most of those guys in his class are either A) too old or B) Just not right for the part any-ways.
I personally think it should be a straight up origin story, the character shouldn't be "Black Panther" at the start of the film...and honestly, my personal theory is that "Wakanda" as we know it shouldn't exist yet either. Wakanda should be like "Nubia"...like, an ancient nation that people in Africa still dream of but that was destroyed long ago. Film revolves around the control of newly discovered Vibranium hidden deep in the crust, a treasure of the once great Wakandan civilization. Film should end with T'Challa as the leader of a new nation-state, controlling all of the Vibraniun in the world, with the sky as the limit for him and his people. Than BP2 comes out and we get to see it in all its glory after massive industrialization.
Regardless, an origin story is the only way this character is getting his own film (series). If we hear rumors of some older head being cast as BP than that's likely a sign that he's just going to be a new Avengers member and will never get his own shyt....