I've run the raid a few times all on normal. With a really good group with high to very high DPS it went OK, lag was the main problem. Other times with pugs we didn't get the boss down fast enough and were smoked by the bombardment. Could the killers circles be reduced to 1 at a time so you don't get instant party wipe? And yes, even high evasion, reflex, dodge toons were getting smashed to -1800 hp.
On normal difficulty I think it should be able to be completed by regular (i.e.not uber) people working together. Good coordination and team work really don't matter if the yellow circles are everywhere wiping everyone out.