Your opinion just lost half its credibility right there.
Going by your Cac logic Joe Schmoe "Cracker" wasn't going to get excited to see Robert Downey Jr, Jeff Bridges, Shaun Toub in the OG Iron Man movie. RBJ didn't have any Major Hollywood "Clout" he was coming off A Scanner Darkly, Fur, and The Shaggy Dog
Joe Schmoe Cracker wasn't going to get excited about seeing Chris Hemsworth, Tom Hiddleston, and Natalie Portman in Thor. Chris Hemsworth didn't have any "Clout" after a 4 minute Cameo in Star Trek
Joe Schmoe Cracker wasn't going to get excited about Guardians Of The Galaxy. A truly D-List cast of characters starring pre Juraasic World Chris Pratt, whose "clout" to that point came from being third lead in an NBC comedy
The FACT of the matter is that Marvel hasn't had one flop yet, using new, up and coming actors as stars with established character actors to anchor the ensemble. Ernie Hudson is NOBODY's "Jobber" he's been acting steadily in film and television for 40 years. Most can cite Ghostbusters, but he's also received critical acclaim for his work in OZ, The Basketball Diaries, and Stranger In The Kingdom. I am sure he would have no issue bringing The gravitas necessary to accurately portray T'Chaka.
This "need for a Denzel" rhetoric is absolutely retarded. Did Captain America "need" Tom Cruise? Did Ant-Man "need" Tom Hanks? When was Michael Douglas's last box office hit?
fukk outta here with that bullshyt