The difference between Sanders and Warren, aside from reparations, is that Warren crafts her messages to specifically and explicitly address black issues. For instance, her answer on the maternity death rate for AA women. Her solution is not going to help only AA women. It'll help all women. However, she doesn't say that. In fact, in a lot of cases she makes it a point not to "all lives matter" the solution. She speaks directly to the black issue.
Aside from reparations and redlining, Warren's solutions have to benefit all Americans. But she just does a better job of communicating how her solutions help black people than the other candidates. Sanders has to learn how to do that.