This article missed several HUGE aspects of the fight.

First, the Burrowers stack a debuff which increases damage taken. This means it's essentially impossible at current gear levels to have the MT also tanking burrowers. An OT is pretty much required.

Second, the Burrowers can be stunned. This is a big help for controlling the stacking debuff on the tanks.

Third, during phase 3 (and I believe throughout the encounter) there's a periodic dot affect on random raid members that does about 3.5k damage per tick. If you keep everyone too low, then they'll die from the dot before they can get a heal. If they're too high in health then the healing from leeching swarm will slow dps down so much that you'll hit the enrage timer.

Fourth, the burrowers gain a STACKING buff on speed & damage when they are beside each other. If you end up in the situation where one tank is trying to tank 4 at once, he's going to die as soon as his cooldowns expire (and maybe before).

These are key elements of the fight that affect what people do and should be mentioned in any article about the fight.