It's not about Luke Hughes, it's about Ty Smith. Nearly every Devils defenseman is far worse when Smith is on the ice.
Dougie Hamilton w/o Smith: 53.29% xGF%
Dougie Hamilton w/ Smith: 44.30% xGF%
Damon Severson w/o Smith: 53.85% xGF%
Damon Severson w/ Smith: 41.45% xGF%
Ryan Graves w/o Smith: 52.31% xGF%
Ryan Graves w/ Smith: 40.88% xGF%
Jonas Siegenthaler w/o Smith: 52.88% xGF%
Jonas Siegenthaler w/ Smith: 47.90% xGF%
PK Subban w/o Smith: 51.77% xGF%
PK Subban w/ Sith: 52.92% xGF%
So only 1/5 regular Devils defensemen can tread water while Smith is on the ice with them. He is actively dragging down the performance of the entire Devils defense and single-handedly making them look far worse than they are.
Smith brings absolutely nothing to the table that other, far superior Devils defensemen don't also bring. He can't skate, he can't defend, he's not physical. He only brings value to the team when he's producing points, and if he's not doing that he's a liability.
If a team is desperate for a young PP QB under contract control for a long time then by all means, help yourself. But Smith is not good. The most valuable things about him are his age and his contract, not his actual play on the ice.