If something really bad comes out, Biden may be out and replaced by soemone more challenging to Trump. Watch what you pray for. 
Although that is a possibility, I just don't think they can drop Biden and then look over Bernie, who's still the race with the clear 2nd place position, without starting a war.
Presumably they would only be able to do this at the convention, too close to the general to risk a war in the party. They are now stuck with Biden, just like they were stuck with Hillary. If I was in the upper tier of the party, I'd be having a lot of sleepless nights.
Plus, who do they have? Cuomo cant be it. Sure the media are really being positive with him right now, but he waited 8 days after Trump said to close down everything to close down NY. He also put in place a total disastrous retirement home policy that lead to many unnecessary deaths of seniors. And there are also some very strong rumors of corruption in his administration in Albany contracts given out due to pay backs. So it is a tough position they are in.
Trump of course has his issues, but Trump is a mud monster. You sling mud at him, he just ends up with more mud looking pretty much the same. Nothing really sticks anymore, but Biden is suppose to be as pure as snow. Slinging mud at him just stands out so much more, just like with Hillary.
This is slowly reverting back to being a referendum on Biden, and the best part is the progressive media is the one pushing it. It was a progressive group that found the Larry King clip.