To me, saying, "Zadina isn't a star and that's a problem," implies that we clearly should've taken someone else with that pick. So which player drafted after Zadina in the 2018 draft is performing like That Player right now in the NHL and making Holland and our scouts look like fools for taking Zadina where we took him?
http://www.hockeydb.com/ihdb/draft/nhl2018e.html
I can accept Quinn Hughes as a respectable answer, though I'm not convinced he's the kind of cornerstone talent you're talking about. (Gostisbehere looked like the second coming of Erik Karlsson in his rookie season. Today? Not so much.) Beyond Hughes, I don't see any reason for getting bent out of shape over the Zadina pick.