Working on this heroic atm with a mixed team (prot pally, resto shaman, 2x arcane mage and a dest warlock), got the first two bosses down and 5 whipes on the last one so far.

Solid suggestions on this thread imo, thanks for sharing.

First boss:
The suggested "trick" of placing a warlock pet (imp) at one of the pillars with the moved to command worked will, pet seemed to get LoS across the whole plattform keeping the lurkers in check.

I keept my slaves together dropping them from follow perhaps a little bit short of 1/3 of the distance from the circling tornados and the boss this to give me some time to manouver the slaves when he calls in his tornados and when they go out. I try to move them as little as possible, preferably just strafing a little bit. At the same time I back out the tank who I try to keep in line with the slaves. DBM addon helps you gauge if a tornado will hit your slaves or not when he is about to call them in.

I also found it helpful to zoom out and tilt up the camera so that I got a good topdown view, made it easier to see the pathing of the tornados realtive to my team.

Second boss:
Almost a tank and spank fight. Suggstion of placing toons in the corner at the right hand side of stairs at the pillar worked well for me, didnt notice them getting hit by any tornados. Tanked the boss on middle top portion of stais facing down the stairs. Key to succes is taunting every time boss does his cone AE else it will be healing intensive. Avoid tornados with your tank for good measure.

Last boss:
Work in progress, having a hard time timining the jump atm and ending up single target dispelling, loosing time and thus getting toasted.