I know some people who worked for her when she was DA, many say the same thing about her...that she's overly ambitious, not relatable, sells people out. This is from reasonable people who are factoring in the demands/sacrifices of power, that she's a woman, etc. It seems the Biden Admin is keeping a lid on her as they don't want her "unlikability factor" to surface.

That said, Biden is rather committed to her for the reasons you stated, she brings in the Black vote, brings in mega CA $$, looks good on paper in many ways (including a kind of crime fighting resume).

As you say also, she would likely be Biden's successor, and I think this is where her shortcomings would really show. Her superficial and defensive callow-ness may turn off many, in a job where relatability is a must. I'm thinking the Dems need to switch her out for someone like Condi Rice, tough/competent/former Secy of State. Centrist Repub I know, but would bring in independent voters, allow Biden to woo center left. This election is too important to screw up.