I've managed to do the worm a few times... ya he is tough My group: Prot Pally, 2 Ele Shamans, 1 Arc Mage, 1 disc Priest all lvl 83.

Few things I've learned and do now.

The dust effect on the ground is a bit of an indicator of his incoming 'charge'. Right as he burrows I plop down a fresh set of totems (earth bind and magma) and then I go consecrate that area as well. Then I run a circle with my slaves on follow around that area, it's super important that none of your slaves do anything to draw aggro of the adds. Half way through the phase i pop elemental pets and pop any aoe aggro effects on my tank. In the second half of the adds phase I pop frost nova (some sort of root) then Thunderstorm on shamans, along with the magma totems and elemental pets should wipe out a chunk of adds by the time the worm pops back up. I have a macro to Lay on Hands my priest which is a good way to draw aggro as well.

His damage isn't that bad so you have a chance when he repops to top up healing. I blow all my dps tricks and am able to burn him down before he burrows a second time. You can survive a toss, if you've got a fairly good handle on the adds (aggro wise), and if you get tossed side ways... not down or up the length of that hallway.

As mentioned earlier in the thread, the gear difference between early 83 (start of Deepholm) and end of 83, is dramatic.