Ann

An obvious difference between Pres Obama and Trump is their capacity to communicate; Barack explaining and motivating to an informed citizenry or Donald spouting nonsense and alienation. 
Words matter,  and ones ability to express themselves is a first order skill that needs constant honing, especially to an important elected official. 
Mazie may be a sympath,  and that can be reassuring.  And when provided questions she clearly has the ability to read them in a committe speaking truth to power. 
But if she shows up at a town hall meeting, purporting to be a member of the "resistance", she should be prepped sufficient to build the crowds confidence in her capacities and leadership.  Answers matter,  a lot.  They build hope

We have malevolent mediocrity  throughout the Trump administration.  A clear contrast gained by articulating a well considered alternative would serve Democrats well.
They all need to step up their game,  it's a serious matter to rid the populace of a populist.