well just some tips..
i think the traps need to be trained in different ways just like every other muscle
for instance there are so many variations to work out biceps but we normally get stuck doing the same thing over and over for our traps
..
try throwing in squeezes and holds with lighter weight and hold each rep for 3 sec
or do your heavy shrugs for 12 reps and then grab lighter d-bells and hold at the top of the shrug for 30 sec
go heavier and do power shrugs (i might get flammed for this) but use your legs JUST ENOUGH to get you through the sticking point..essentially use them as a self spot
do down the rack d-bell shrugs starting with something you can only get out 10 with and then drop 10lbs and keep goin until you cant raise your traps (do not do this every time and be careful what other trap exercises you do so you do not overtrain)