Biden's primary strength was the Black vote, a demographic obviously underrepresented in the NH Dem primary compared to the national primary electorate. Similarly Trump may have trouble in NH compared to other primaries because they're more educated but should perform better down South without Cruz splitting the evangelical vote.
It's definitely interesting though how Trump's coalition from 2016 changed though. I remember New Hampshire was always considered the safest of the early primary states for him. He had more appeal to independents and ideologically moderate voters back then.
