Trump has huge unfavourables. That is what the Dems are banking on.
He will run on immigration which can be the deal breaker.
If there are not enough policies, people may just stay home.
That is the danger for the Dems.
I'd be shocked of this wasn't one of the most attended elections ever. Policies might make a difference for those on the far left of American politics (so not that far left, but I digress), but this is going to be about Trump, who is highly unpopular.