HRC was not a good candidate. She was qualified, and she likely would have handled this virus differently than Trump (the "war-time President!"), who now has the blood of tens of thousands of American deaths on his little hands.
She had 5 major flaws as a candidate, in my view.
1) She stood by her man, just like Tammy Wynette said she would, which for many was unforgivable, despite it being none of their business how two people cope with the frailties of their marriage.
2) She didn't know how to hit back, when she got hit, without it sounding like she was delivering someone else's lines. She was a great student and could learn her lines well, but she does not speak well extemporaneously, and she never sounded unrehearsed. That is the kind of person who sounds inauthentic to too many Americans, who are natural born skeptics, as a rule. She reminded me of those teachers who had the perfect lesson plans, and are competent as long as they had motivated students, but don't know how to handle the smart-ass who sat in the back of the room.
3) She came across to many as entitled to the job of POTUS, a certain "who else but me?" That was a turn-off to many. The fact that she didn't go to Wisconsin, underscores the perception of entitlement.
4) She appeared to take Bernie Sanders's criticism personally, and she didn't show that wing of the party a path towards what they were demonstrating they needed and wanted. She didn't know how to solve discord within her own party, and that was a problem for getting turnout, especially in states that were in play.
5) And lastly, she was a she. No matter how far you think you've come, America, you still don't trust a woman to get the job done.