She's a female Obama. She's not what's going to carry the day against Trump in 2020, however.
Trump can only be beaten if the 2020 electorate views him as incompetent. In that case, beating him will require a Democrat with significantly more experience at the Governor/Senator/Cabinet level than Kamala Harris has.
It's hard to argue that Harris is inexperienced, considering she was attorney general of California for six years, and district attorney before that.
She has political experience, but those credentials are the credentials of someone being proposed for a lesser Cabinet post, or something like Solicitor General. Presidential candidates who have careers in politics are expected to have served at the level of Senator or Governor, and (usually) for at least one full term.
We have seen folks like Rubio, Cruz and Obama being boosted early in their careers based on racial/ethnic factors. This worked for Obama due to the time of his candidacy. It didn't work for Cruz and Rubio because they came up against a candidate with a lifetime of executive experience who was, actually, a gamechanger.
Harris isn't Michelle Bachmann, but she's not someone who'll oust Trump on the basis of competence. Trump is, slowly but surely, moderating his style and demonstrating "leadership". The "resistance" to Trump is being crystallized; the "resisters" are seen as in the minority versus a "silent majority". If Trump is going to be beaten in 2020, it will take the perception that he is incompetent, coupled with the perception of extreme competence by the Democrat, who will be expected to "right the ship".