IMO Biden or someone like Biden would be the best bet for the democrats in 2020. They need to pick a moderate democrat to lure in the centrists.
Someone like Biden in the sense that a moderate would more likely appeal to the base. As long as they can find one who will meet the approval of the far-left fringe that seems to have taken control of the party.
Biden running would be a gift to the Republicans.
The Archive link is timing out now. Here's the USA Today article of you don't mind giving them traffic.