I already acknowledged that Biden has plenty of negatives as a potential nominee.
Again, my point is Hillary had considerably MORE negatives.
You are focusing mostly on issues. Quite frankly I wish every voter would focus on issues and policy as much as you do.
Having said that, put on your political reality hat. You know as well as I do that political campaigns are as much about the superficial crap as they are substantive stuff. Look no further than how the debates are structured. It's all about zingers and talking points. How can any candidate even come close to addressing a complex issue in 90 seconds.
Regrettably, it's talking points, zingers, bumper sticker slogans and the ability to work a crowd that sells in politics. I know you know this.
On the superficial side Biden crushes Hillary. It's in this area that Warren is going to have problems. For left-leaning political junkies I'm sure she's a very attractive candidate. But when it comes to the things I just mentioned, she's a liability.
Also, when it comes to policy preferences you come across as believing you are a centrist. You're not (I'm not claiming I am either). There's a reason why 'moving to the center after the primary' is a thing in presidential elections.
As an aside, in '16 I was flipping channels and when I was about to skip past Fox News (I quit cable news years ago) I noticed Rubio on stage by himself, holding a microphone and addressing the audience. Out of curiosity I decided to watch. You would have loved the format. Each candidate (if memory serves it was only Rubio, Cruz, Kasich and maybe 1 or 2 others - at this point the field of candidates had already winnowed and unsurprisingly Trump was absent for this) spoke for several minutes about a narrow issue and were then asked a series of clarifying questions, not by an audience member, but by an expert in the field of discussion. I was impressed by the breadth of knowledge each one had on the subject matter and I was impressed by how, with one exception - Rubio was evasive on 1 question - the candidates shot straight and answered the questions.