I think people are asuuming the AOE range is going to be equivlent to provoke. My guess is that the taunt effect is going either be melle range, about 2 yards, or slightly smaller. This means it would be good at keeping aggro once you have them near you, but it isn't going to really grab anything very far away from you. That will be what provoke and taunt are for.
That means, you still have to pay attention and grab straglers. It will also be of shorter duration than provoke and taunt. This mean you are going to have to keep up a constant barrage in order to keep it going.
People who know their powers and how to use them well will still be better than people who use them blindly.
If I am not mistaken, most tanks are Inv, which allready has an PBAoE taunt in Invincibility. Does that mean that Inv tanks are just provoke bots, which takes no skill to play?
JVB