Having Sam Wilson, an African-American, become Captain America may seem like it's a bold move. And it is.
From a Caphead and comic book reader's point of view, it makes sense. (As I said in this posting in which I reacted to the news.)
1) Since Wilson has fought alongside Cap (Steve Rogers) for years as The Falcon and been one of his most dedicated friends, it makes sense for Wilson to take up the shield and Cap's mantle. Rogers naturally would look for someone he trusts to take his place as the Sentinel of Liberty. He's always trusted Sam Wilson and visa versa, so he would trust Wilson to make a great Captain America.
2) There's a long history of heroes' sidekicks/partners taking up their protege's identity. Case in point here: Bucky Barnes became Captain America while Rogers was considered dead. In fact, Barnes remained Cap when Rogers returned from the dead (i.e. being suspended in time) and took on the role of The Avengers' federal recruiter as Commander Steve Rogers.
But Wilson being Captain America -- for however long that is -- is symbolic for a more important reason: This means Cap, even without the Super Soldier Serum, isn't just the epitome of American patriotism, loyalty and most importantly, America's ideals; he is an everybody.
In essence, Captain America doesn't just represent America; who Cap is and what he stands for is the melting pot of the United States of America.
Granted, being a lifelong Caphead, I consider Steve Rogers the real Captain America. The government created the identity just for him to be the first of many Super Soldiers.
In the same way, Bruce Wayne is the one and only Batman. And while it's fun to read about other heroes taking up the Mantle of the Bat, there's nothing like the original. Wayne is what makes Batman tick. (A lot of fans think Bruce Wayne is just a mask for Batman, but I argue you wouldn't have a Batman without Wayne's life experiences, most notably seeing his parents murdered before his eyes as a young boy.)
Can only Steve Rogers be Captain America? Rogers best embodies what it means to be Cap, but several people have taken it upon themselves to replace him while he was in suspended animation or gave up the mantle voluntarily. And those Caps were nothing like Rogers in many ways. Those men included another patriotic superhero, a demented clone of Rogers, a street punk who thought he could be as tough as the original Cap, a former professional wrestler jacked up on steroids and Cap's former sidekick who was turned into a terrorist and international assassin.
Those versions of Captain America represent a decent melting pot of what makes America, well, America. Captain America represents everything the U.S.A. is.
True, all those Cap replacements I mentioned where white men. But who cares? Being Captain America isn't a racial thing. And it never should be.
Since the United States of America is a melting pot of people from different backgrounds with their faults and foibles, why shouldn't its quintessential hero? There's no reason a black person, a Mexican-American or a woman can't be Cap.
The creative decision to make Sam Wilson, one of the first African-American superheroes, the next Captain America is a bold move.
In fact, having a black Captain America is a beautiful move -- one that symbolizes the diversity in this great country.
The newest Star-Spangled Avenger is a black man. God bless the diversity of America!