NHL teams watch reams of video footage....they can readily see what individual players are doing to break them down, and they focus on taking that away.
So far this season, it's readily apparent what teams are doing to neutralize Hughes. He's being victimized by the 'soft dump in' into his corner and then two forecheckers box him in. Even if he beats one guy, the other guy gets him into a board battle where his stature and lack of 'heaviness' works against him.
It's no mystery why he's been on the ice for more five-on-five goals against than any d-man the in league. Now the ball is in the Canucks court to adapt. Maybe they have to think about pairing him with another offensive, rushing d-man. Come to think of it, a Hughes-Rathbone pairing would be an scary adventure, but fun to watch.
Whatever they try, it's up to the Canucks coaching staff to make the next move. But they should have anticipated this before the season even started.