On my experience their quest is usually completed on turn 4. But druid also completes on turn4 a(with coin on t1), lackey shaman on 5. And shaman quest reward is much-much stronger, after quest complete it's just demolition with that double battlecry lackeys. Also if rogue will become dominant - cwar will start farm them easily.
BTW druid sucks, it runs out of steam so easily.