Call it superstition but i find if you have autolock encounter on the pet seems to taunt less; maybe the taunt cycling bug is somehow tied in to this.
Remember swarm pets transfer all their aggro to you when they expire or die. If you stick roaring flames and aqueous hunters at adept III or higher on a mob then chain nuke your pet is likely to lose aggro after exactly 45 seconds. I usually hit the mob with a stun as aqueous is about to expire; then if the pet loses aggro it buys you some time to react.
Bear in mind if you can cancel all DoTs then the root is unbreakable. If it's a lost cause and the pet is never gonna get aggro back just sacrifice it and burn the mob down with shattered terrain / frozen by time / re-root.