Kunan I've seen many river with guys using long leaders like the Lewis, Kalama, Satsop etc. my theory is that the fish open and close their mouths constantly and with a long leader it greatly improves the chances of the line pass by the fishes open mouth and when you set the hook the drag of the water causes the hook to go into their mouth.. There is a big difference on the feel of a grab with a 3-4' leader opposed to a 10-12' one.. Then longer one seems like a slight pull like your hung-up...
But thats just my opinion