I don't think the league is trying to eliminate hits so much as they're trying to refine hitting so that it results in less injuries. But all of that is still at the mercy of the guys on the ice;
as the game has gotten quicker, and as teams have emphasized puck possession, the need for "stay at home" defenders has lessened.
Coaches are no longer preaching a block the shot philosophy except for weirdos like Tortorella. I mention this trend because your stay at home types tended to be physical. If you want to throw a big hit, you be better be able to skate. So I think the change has been more philosophical than anything. But I also think Dallas is unique: our top defenders are undersized, therefore, are taught to go after the pick instead of engaging in a physical battle they're at a disadvantage on. Dillon is kind of an awkward skater, but I doubt he's being coached to not hit (remember his shot on Loui last year or this
monster slam on Andrew Shaw?). I think he just suffers from an identity crisis; has has the physicality to be a defensive defenseman, but wants to be involved in a rush up ice and play run and gun instead.