We have the DPS ignore the adds completely on our attempts. they stack in tight to the boss and focus entirely on the boss.
We are fortunate enough to have a Frost DK in our group, who with Blood Aura, kites the adds around the back of the room for the whole fight (Howling Blast, D&D to keep aggro). The Priests will drop light wells out for him to click every once in a while, but it is important to heal him as he will take splash dmg. If everyone is in tight, and the columns only appear on him, we have a free reign to tank and spank magmaw, meaning the fights are much shorter.
It is doable with a Prot Warrior too, using Shock Wave and Thunderclap, but he will take more dmg so will need a dedicated healer (harder for 10-mans no doubt). Our Warlock CO recons it could be done with a Range DPS if their dmg was high enough to counter any healing aggro, but the DK is so successful we have run with that each and every time
(I should say we are a 25-man guild, but this tactic worked in 10-man last week with Alts, so will be good for if your gear is not quite up there)