I think it's a good change. Tanks still get to find something to use and separate good tank from the bad while dps doesn't have to worry about the now-trivial threat management. I mean, waiting for 5 seconds or pressing feint now and then doesn't really add much to fights. In contrast, it's a stale mechanic.
This way blizz can go more crazy on fights too because dps will be busy with dps, tanks with survivability, healers with keeping stuff alive. They're all connected but still doing their own thing.