A plagiarist in 1988, this is like saying Gore's 2000 candidacy was soomed because he smoked weed a long time ago. It's way less important than the emails issue, which hasn't seemed to sink her.
The Crime Bill could be a real issue, but otherwise he's a highly prominent Democrat with a long history of public service who could reasonably take the mantle as Obama's successor. I don't know if he would beat Hillary in the primary but I definitely think he would be a stronger GE candidate.
And yet the majority of anti-Hillary sentiment is grounded in the same time frame.
Only absolving Biden of his past problems is not going to happen.