It seems the prevailing discussion on the Democrat side is that Joe should strongly consider picking an American Black, preferably female. But things that resonate within the party and the media may not necessarily resonate in America.
I view the VP pick this way. Joe Biden is underwater, I don’t care what RCP says. He is likely to lose, and may lose really, really big. As such, you want your VP pick to give you a boost, not merely shore up previously safe demographics. Ideally you would want the pick to help you steal crossover votes or a demographic or a state or two.
Things other than source state or race can be much bigger in a general election. Personality, resume, some particular specialty or calling card that can appeal across party lines. For the Democrats, that might be a big name sports figure (AJ Foyt, Dale Jr, Danica Patrick, Terry Bradshaw, Michael Jordan) or impressive military hero (John Glenn, pre-scandal David Petraeus, Michael Flynn if they had not tried to ruin him), or a notably centrist or crossover politician (Joe Lieberman, Joe Manchin, pre-2000 Al Gore before we knew he was nuts).
I would say go for some kind of very, very positive and vibrant persona, male of female, of any race, that does not sound like a socialist, free of scandal, and who does not have a specific record of making headlines pissing off undecideds in battleground states, and who might geographically help tip a significant state or several. If that person happens to be black, or a woman, so much the better.
To get back to the main topic, yes they are hemmoraging black votes, but in the search for meaningful battleground votes, there are more meaningful votes to be harvested by picking for personality and lack of socialist bona fides.
The payoff here? Stacey Abrams is actively and shamelessly lobbying for the job. Others prominently mentioned are Kamala Harris and Susan Rice. Outside the black female crowd, Amy Klobuchar seems to be a hot name, Andrew Cuomo and Michelle Obama also getting some mentions. Each of those is a terribly flawed candidate.
I can’t think of anybody, a single person, who makes a good pick. Fortunately, it’s not my job to help them.