She can get her to put a plank in the platform, maybe, but after the election, President Hil (if that’s the outcome) will listen to no one.
A lot of my liberal friends are pushing a Clinton-Warren ticket. I ask them what makes them think Warren would have any interest in a VP candidacy when she has said repeatedly that she has no interest in running for the top spot. Then I point out what you just said, and ask them if they believe Warren is stupid enough to think that she would have any influence in a Clinton White House. I doubt she would even be invited to cabinet meetings.