People are going on about this as if its something exciting, original or bold, but its none of those.
Cap has been replaced before, become a skinny weakling because his serum was removed and he has "died". Thor has also been replaced multiple times, including by an alien (Beta Ray Bill).
Everyone knows this isnt permanent. Just as they knew Rogers death wasnt permanent. Bruce Waynes death wasnt permanent. Supermans death wasnt permanent. Tony Stark as a teen ager wasnt permanent. etc etc
And sources reporting on the Cap story are acting like replacing an iconic character with a black dude is original, like a black dude never replaced Green Lantern or Iron Man. And lets not mention Nick Fury.
At least when DC killed of Barry Allen & Supergirl back in the 80s, it was something that lasted years. And in Barrys case, there was always a feeling that he might never be resurrected. (although obviously DC just couldnt resist in the end)
Then of course theres the whole "what will it mean for the films?" .. absolutely nothing probably. Its not like the films are spot on conversions of the Marvel universe. Did Pepper Potts marry Happy Hogan in the films? Was Mandarin a British actor in the comics? Was Bucky the same age as Captain America in the comics? Was Jarvis a computer in the comics? etc etc etc