I think we'll have to wait and see on this one. I don't think Blizzard wants to go back to the days of raiding while staring at Omen. I believe they still intend for an equally geared, equally skilled tank to have a good threat lead in any given encounter. I don't think the tank will be 65% ahead of the DPSer in second place is all. I think they're shooting more for the situation where if the tank is at 100%, the second place DPSers are hovering around 80-90%, instead of the sub 50% they are now. But this is all just speculation.
Also I still can't see how we will not be balanced around having Vigilance, yes they stated that they won't balance us around it but they also stated that DPSers would catch up to us after Naxx25. Doesn't this turn Vigilance into a flat 10% tps increase for us? Not a stable 10%, since we are not in control of this threat but wouldn't it be a significant huge chunk of our threat? How could we not be balanced around having it?