I wish there were more visual cues, or maybe just the player base doesn't care. I was fighting a couple of named Daedroths and one of them I had locked down with CC. Some random guy came up and instead of helping me fight the one I'm currently attacking, he instead decided to hit the CC'd one... which then tore him a new a-hole and it then came after me. Fortunately I was able to lock it down again with a sliver of health trying to handle them both, but when he came back he did the exact same thing and died again.
Maybe mobs can have a ring of stars or birdies around their heads to show they been CC'd not just staggered over, maybe people don't see it? What do you think?