For all the similarities btw Trump and Sanders takeovers, one difference: Trump accelerated realignment of the parties along new class/education/gender lines; Sanders nomination would probably decelerate that realignment.
Polls can change but in the polling we have now a Warren or Buttigieg nomination (notwithstanding their policy differences) gives GOP inroads w/minority men while suburban women keep moving Demward. Sanders holds more minorities, doesn't win as many UMC suburbanites.
So the parties hold in their 2016 alignment or even slip back a little toward 2012 dynamics, rather than moving further toward a upper-middle class liberalism/working-class conservatism formation.
This assumes that Sanders will be a more effective populist than Corbyn, who did accelerate realignment; time and Trump ads will tell, but I think we have enough data to make that a reasonable assumption.
