I don't have neccessarily the same problem you do, since I run 5x shammies, so no tank. I noticed they were a problem early on when I started running MT. My kill order is generally: #1 priests, #2 scavengers... the others don't matter too much except the darkweavers which can summon friends if he is left alone too long. Since you have a tank the priest aoe shouldn't be a problem, so just pop your trinkets and kill them before they get to you, or if there are 2, the first one should be dead and the second one hurt before he touches you.

I'm not sure how they work with your tank, but if you find that they gouge/charge you quickly, perhaps consider pulling with your DPS and then prying them off you with your pally.