Much more concerning than anything else that was mentioned in this thread, is the HUGE problem for her that nobody here has remembered yet: the fact that she is the only one of the top Dems who is losing to Trump in all three states that gave him his 2016 victory. The others aren't doing so well there either, but at least Biden is beating Trump in all three, although now by really small numbers (2%) which might reverse once Trump decimates Biden in debates, something that wouldn't have happened 8 years ago when Biden's mind was sharper (he ate Paul Ryan alive in their veep debate) but will definitely happen now that Biden looks and sounds like a demented shadow of his old self (which wasn't that great to start with - gaffe-prone Biden has always been a bit stupid; but at least he was combative, and not the fool who searches for words and seems lost like an old man with Alzheimer's).
I think the Dems will lose to Trump. Maybe a way to avoid that would be for Biden to pick a very young and energetic veep so that people feel reassured that if he croaks or gets incapacitated, the veep will take over. Maybe Biden and Buttigieg in a ticket? Better than that, maybe, is if Buttigieg grows in polls and takes the Dem nomination but then gets a black veep able to attract support for the ticket from African American communities that are, so far, totally cold towards Buttigieg. The problem with that is that Buttigieg would have to win the nomination first in order to be able to propose a veep, but he can't win the nomination without black support, so he will not get to the point when he'll be able to reassure the black community by picking a black veep.
But see, when the victory starts only getting viable through some extreme scenarios, we know that a campaign is in trouble.
Brace for four more years of Trump, folks. That's what the incompetent Dems will be bringing upon us, again. They idiotically assumed that because Sanders challenged H. Clinton, it means that the voters wanted extreme left positions. No. Hillary Clinton still beat Sanders by millions of popular votes, which I suspect would have been hers even if the DNC hadn't helped. She lost to Trump because she was a colossally incompetent campaigner and one of the most unpopular candidates ever. Not because she was a centrist. The core of American votes are still gravitating somewhere around the center; they are definitely not on the extreme left of the spectrum (like Obama, who was able to win twice, keeps telling the candidates).
So, instead of contrasting Trump's impulsive, unstable, corrupt, and narcissistic ways with a solid centrist candidate with simple and straightforward reassuring centrist messages to restore the dignity and honesty of the office, which most people would relate to and find to be a great relief and a valid alternative to Trump, the Dems go and propose a bunch of far leftists and a couple of centrists, one of whom is demented and the other one is gay (not that I find that the latter is a problem, but a lot of people do).
Great job, Dems. Thank you [insert sarcasm here] for four more years of Trump!