This is an interesting philosophical point to me. Do you think the president's role is MORE:
1) to be right (to have moral authority, to set the agenda for the country, to make the case for what is right)
2) to do things (lead, manage teams working, come up with the plans)
Again, we can talk about Bernie not building consensus or getting enough done, but he voted correctly on DOMA, Iraq War, every social issue under the sun. He was never a Republican, he hasn't been evolving on the issues, he wasn't instrumental in creating the war on drugs and imprisoning half the black population. He's been the consistent moral authority on the left for a really long time. Simply by doing such things, look at who the centrists in the 2020 race are vs the ones in 2016. The party has moved left based on his policy positions.
Another way of dividing candidates--is the next president's job:
1) structural reform (electoral college, SCOTUS, filibuster)?
2) return to norms (work with Republicans, address polarization, try to get back to status quo ante-Trump)?