In my experience, having the dk in frost presence while normally dpsing them with 2-3 ranged dps going all out on AoE is fine . The dk never has time to actually start kiting.

Our arms warrior that feels like boosting his dps also heroic leaps in and starts cleaving when the adds are

You can also get a rogue to ToT to one of the ranged and then spam FoK on them to slow them down and do big AoE damage.

Wonderful! I will do this next raid. Does this mess with the jumping on Magmaw?

Also, I assume hungering cold is super helpful here.

If Hungering Cold ever became effective in this game, I'll eat my boot. Why use it here? You want to kill the worms, not use ineffective skills on them.

Another effective cheese if for a demonology warlock with decent pet skills to toss his Felguard into the parasites as they spawn and use Felstorm. It won't always be up, but it absolutely destroys the adds. Also, Felguards are immune to the infest, and thus Parasite Evening would be cake if you brought 2 Demo Warlocks. Granted, the DK cheese is probably easier. But my group doesn't have a DK, and they do have a Warlock, so that's our strategy.