Outside of the truly franchise level defensemen, most need 2 years in the NCAA, unless you produce (more than) dominant 2 way results as a freshman. We've seen Makar, Hughes, Werenski, McAvoy, Sanderson all go back to the NCAA for their sophomore year and it helped lead to elite NHL results sooner.
Not quite convinced Carels, DuPont, Lin, Rudolph, & even Verhoeff are elite enough to be 1 and done NCAA players, but DuPont's underlying numbers have suggested better results in the Dub than his raw numbers so far, so he could be in for a big jump moving forward.