Since his brother Jack was lost for the year, Luke Hughes has 16 points in 13 games, including six multi-point games in that time, and he has averaged 24 minutes of ice-time, with five games over 25 minutes and the Devils have been able to play to a respectable 7-5-1 since the injury to Jack.
Luke struggled for some stretches this season, but the Devils consistently kept the faith in him, increasing his ice-time each month this season to the point where he is now playing like a #1 defenseman with a ton of confidence heading into the post-season and into next season with a big fat long-term extension on the horizon.
Contrast Luke's icetime and role to that of Clarke (drafted 4 spots later). Clarke's icetime has been all over the place, and the Kings couldn't build upon his fast start and the confidence he should have had. Clarke was scratched for multiple games, played some at forward and has not played over 20 minutes in a game since November 13th.
I wonder where Clarke would be if he had been given more icetime, more PP time and had never been scratched. I still don't think there is much difference in God-Given talent between the two (Clarke may even have more), but Hughes at the end of D+4 is just multiple levels more impactful of a player on a similar NHL team and taken pretty close in the draft.