Just thought I would point some things out.
healing aggro is 50% and is divided equally amongst all enemies in a fight,. tanking threat is 150%, and then some abilities increase it. For example, my shock generates 2.15 times the damage in threat, discharge and wither generate around 3 times as much. all other abilities generate 1.5 times the damage.
Taunting puts you over the current threat by 110% when taunted in melee range and 130% when taunted from more than melee range.
Also, My rotation is nowhere near 1000 dps. I might get lucky to get a 2-3k shock, 1-1.5k wither and minimal damage on discharge. My FL ticks for 1k. assassinate can go to 3-3.5 k if crit 2-2.5 k normal. There is no way I will get close to 1000 dps and I got PTs and assassins that can gnerate bursts for 2400 dps.
I have never seen a tank lose aggro while kiting, what can happen is if you have a sin/jugg or PT dps, they might taunt inside the shield so that the adds inside the shield dont hit the healers, and if they are not done properly, they might get storm aggroing on them.