I think most Democrats likely feel that way, although they want it to be a smooth change...
Joe was meant to be a moderate, do little harm President to try to set us back on some stable footing as a nation after the nonsense of the last 4 years of Trump. For the most part he's done that job ok, but he's been unable to really move the needle on any policy as he doesn't have the charisma to really push people on issues one way or another as prior President's have had. He works really, really well in backchannel diplomatic means and I think he's done an exceptional job rallying our allies and I do give him major props there. There's no way the world would be as united had Trump been in office when this all went down. But as for Domestic issues, the Democrats aren't going to get much movement with him.
Here's hoping he decides not to run and the Democrats can find a really good candidate to come forward. If they just re-run the same stack of candidates from last time however it'll be problematic. They need to find an Obama or Clinton style President who really is middle of the road but can find ways to energize that further base, who recognizes that "It's the economy stupid". If the Democrats can keep the economy good for the middle class, then they'll be able to slowly push whatever progressive ideas they want through. The problem comes when they move too fast with change and when they stop trying to keep a strong economy in place.
Find a President who is charismatic, feels a bit more middle of the road, and pushes America further to the left in slow, manageable ways and we'll be good.