The can have a new black panther without recasting. Let Shuri do it for a little while then have someone challenge her honorably and take the throne later at some point. Black panther is a mantle that is passed around anyways.
T’Challa has ALWAYS been the Black Panther though. Its only him and for a brief time Shuri. There is no “someone else” within comic cannon to pass him off too. I guarantee that if they create a character from scratch it’ll flop.
Recasting at some point, whether sooner or later, is inevitable


there will be pushback in the black community. His only other hope would be to get McQueen. And even still that might be a problem for black America because he's not a black American.