It's perfectly fine if nobody dies and there's enough DPS and everyone does mechanics without fail. However, asking that of pugs can get frustrating.

Seriously, as soon as someone dies, it all just snowballs from there. I have to stop to get off raises and apparently the other healer cannot react quickly enough to the copious amounts of aoe damage going out as soon as i start casting it. I have seriously just watched as my cohealer just stands there after megaholy goes out while i was getting raises off. Then by the time the tank buster goes out, the tank is way too low and dies, and it just keeps rolling downhill from there.

Since people aren't out gearing it yet, it requires a certain level of competence that some pugs don't have.