180-200 million hp in a 25-30 man raid is still very little. That;s 18 dps doing 180-200 million (10-12 million each) over a generous cast time. Assuming your DPS have CDs and can do 1.2 mill dps (Easy with 935 ilvl, ToS 4 set and CDs), that's 2 dying in the first 20 second cast then the 3rd dies on its second cast. - The healers are the only real problem, since even with chain lightning there is plenty of room in all the safe zones to be 2 yards apart. And the fire adds still melt is dps know how to target switch. It's not so much about high dps as it is competent dps who can target swap or save CDs.