Not the right board, but my suspicion is that Pence would win the GOP nomination because he is the incumbent VP, and Bernie or Warren would win the Dem nomination because of the increasing progressive voter turnout. Either way, Pence would win both times.
And how would Sanders or Warren win with 5+ credible candidates from the left of the party
On the Republican side, yes, Pence will definitely be damaged, but i don't think some like Amash or Carson are strong enough candidates, and others like Cruz would just support Pence. On the democratic side, yes, you listed a lot of great candidates there, but seeing the progressive movement grow that large in 2016, I only see them, and maybe Deval Partick or Kamala Harris become the nominee.
