No idea if he’d be interested but Mark Kelly would be a great candidate to try and win independents.
At this point the VP has the most legitimacy as a successor and given the situation we’re forced into she’s unambiguously the option. That doesn’t make it good, but it makes it better than all the other terrible options that involve a free-for-all between candidates with no opportunity for voters to weigh in.
The best possible outcome at this point is for the establishment to quickly and unanimously get behind Harris. Again, it’s not necessarily a good outcome. But it’s the best available to us thanks to Biden waiting for the last possible moment (again) to come to this realization.
Basically, the DNC's options are the people who failed to get through the primaries in 2020 against Biden and maybe Whitmer or Newsom.
I just do not see Harris getting the middle/undecided, and it's 2016 all over again, if not worse, because SCOTUS has the deck stacked if it's even close.
The polling seemed too convenient. I don't have a link handy, but the best poll process I saw after the debate did show Harris doing better than Biden, but she was still worse off than a few of the other Democratic potentials.
Maybe? Gretchen Whitmer might be a strong candidate, off the top of my head. But I'm struggling to think of a nationally known candidate with super-strong positives that would be a viable alternative. (That's also true for the GOP IMO if somehow Trump was out.)