Morris Chestnut would have been a good choice in 1996. In a perfect world Dijmon Housou would be a great choice for the role, but hes hella old. His accent would of been perfect. He could probably play T Chaka now. I used to support the idea of Anthony Mackie playing the role but he's doing Falcon now. Chiwetel Ejiofor would be good too but he's 35 years old now and would be hard to pull off a young T Challa. My pick for young T'Challa origin story would be Micheal B Jordan. He's was tremendous on the The Wire, Friday Night Lights, and hes killing it right now in Fruitvale Station.
i think the fact that he was not as fast and thats why he died makes its more emotionally gripping. In spite of being the weakest link he still was needed to save the world and in the process die himself. Its the weakest link that I personally identify with more than the fastest, strongest, greatest.
While Black Beetle did best Superboy, Wonder Girl, Lagoon Boy, Bumblebee, Robin, Batgirl, Miss Martian - none of them are particularly powerful in terms of sheer strength (and Miss Martian never got to use her telepathy either).
And he wasn't even capable of defeating Blue Beetle, who by all means should have been far less inexperienced than him at using Scarabs (though Black Beetle was arguably trying to rescue Shimmer, so there's that).
Also he had an atrocious showing against the Runaways and Arsenal - I know they could never beat him, but it was still pretty bad considering they're so new to the superhero game.
And he never technically defeated Mongul either - him and Green just stuck him in a cage. Honestly, the dude hasn't even scored even one win through the entire season.
On the other hand, Thor was able to hold Manhattan long enough for the island to sink back into place, his thunder was the finishing blow that defeated Graviton, he was able to summon enough power to not only deflect Kang's hyper-laser-thing, but also send it flying back to Kang's ship.
He was also able to reseal the Casket of Ancient Winters, able to retrieve his hammer from Odinforce Loki's shield (which I assume was made of the Odinforce as it took great effort on Thor's part to get it), and he could overload the Skrull Empress' ship through sheer lightning.
He also nearly defeated Vision until the android escaped, defeated Rulk with one well-aimed hammer-toss, and took out several powerful Kree Sentries with lightning strikes.
Also he threw Mjolnir through Galactus! Through the Devourer of Worlds!
Sure he had some poor showings (getting knocked out by Wonder Man, failing to defeat the Avengers robot-copies), but I think those are more PIS than anything.
But who knows, maybe we haven't got to see Black Beetle's full capabilities either. And also, Black Beetle has had less appearances than Thor so it's difficult to accurately gauge him. But based on what's been shown so far, I'm sticking with Thor.