I think often times fans speak incorrectly in terms of value. A #5 defensemen or 9th forward likely isn't adding much value to a team. If anything, they are losing value. If you compare them to the rest of the league, they are objectively in the bottom half of NHL'ers. Each team is competing to have enough players on their roster that add value, and if your players aren't in the top half of value in the league, they aren't going to be adding value compared to the players they play against. Fans speak about anyone who isn't a terrible contract or AHL goon in good terms, but a number of them that are spoken about in good terms are hurting NHL teams.
The question is how much value a player like Quinn Hughes gains or losses for your team. They are different players, but I look at someone like Kevin Shattenkirk as a comparable. Some claim he's a top pairing defensemen because of points and analytics, others say he's a bottom pairing PP specialist, others say somewhere in-between. If he's top pairing, he's going to gain you value. If he's a bottom pairing PP specialist, he's losing you value. Somewhere in-between and its a real debate whether he's losing or gaining value. I watched Shattenkirk for a few years on my team, and I thought he was more of a bottom pairing PP specialist. However, he struggled with injuries on the Rangers, so I can see in a different situation that he's a middle pairing defensemen. I think it's going to be somewhat similar with Hughes.
I personally think he's going to lose a lot of value at the other end of the rink. I think he's going to accumulate a lot of positive and a lot of negative value. He'll be a high activity player, but will that ever result in more than slightly below or above league average value for a defensemen? I don't think so. Considering most teams have 7 defensemen on their roster and a few have 8, that would make league average around a 3.5. I'd place his likely value somewhere between a high-end three in his best seasons and a low-end four in bad seasons.
Jack Hughes is going to also lose a lot of value because he's being used as a center. There's a lot of responsibilities for a center that there aren't for a winger. Face-offs, increased defensive zone responsibilities, increased puck battles in the corners, increased puck battles against bigger players and a lot more middle of the ice play required. I don't ever think Jack will be better than a player who is league average defensively as a winger. Even that might be a stretch. However, if you are putting a guy who is probably a net-negative in other areas of the game from the wing at center, you are going to lose a lot of value. And being realistic, he's probably going to be a bad defensive player at wing, so we might be talking about one of the worst centers in league when it comes to value lost outside of scoring.
I think Jack will be about 1PPG, give or take a few, for his career, but that'll come with a lot of lost value in other areas of the game, which is why I don't think he'll be one of the elite players in the league, despite scoring like most of them do. However, I still think a player with his style at center or wing will lose less value than a defensemen of that style will lose. Speaking again in terms of value, I don't know if Luke ever gains as much value as Jack or Quinn, but I'm near sure based on what I've seen so far that he will lose a lot less than they will.