There's only one candidate for the DNC head and it's Keith Ellison.
Under him, and with the support of people like Warren, Sanders, Canova, etc., I can see the Democrats taking back Congress and winning in 2020. Going the Perez route would surely be repeating the mistakes of 2016 all over again, and would be giving up the biggest momentum the party has had since the nation universally hated Bush.
It's a pivotal moment for the future of the party, and I (and many others) would he severely disillusioned if they voted for a continuation of the Clinton-ist, New Democrat, faux right-wing agenda of the last 20 years.
For my education, why would Warren or Saunders not be considered for this role?