I'll take prospects who actually perform in the NHL than the WJC.
Vorobyev is a good example, good passer, but mediocre skater and despite his size, was allergic to contact, so you had a playmaking center who wasn't fast enough for a scoring role and refused to use his body in a checking role. Even in the KHL it took him three years to win a top 6 job.
Sushko simply flatlined in the AHL, D+1, D+2, 60 and 51 points in the OHL, 32 and 17 points in the AHL, 16 points in 63 KHL games. There was nothing there to develop.
Holmgren/Hextall didn't draft many with offensive skills after the first rd, Kase but injuries derailed him, he wasn't his brother. Kalynuk pretty much flatlined, cameo with Chicago, now in his 3rd AHl season. And so on. Ratcliffe could score goals in junior hockey, but couldn't translate that to the AHL (25 goals in 181 games, compare to say Desnoyers), much less the NHL.