In order to get the job done this time around, Durante mentions in his thread on the official forums that he had to do some pretty significant Stamina stacking, and his DPS was quite nearly nonexistant with the spec and equipment that allowed this to happen. He did just over 900 DPS over the course of the encounter. The raid didn't seem to need to stack any extra healers for this, but the five that were there had to be on top of their game. One attempt was cut short when Bubbles ate a pretty hefty crit, and pets can't be crit immune. Threat was a little dicey at first, Durante says, DPS really needed to hold back for awhile. They managed it though, and that's really all that counts.
I wouldn't say that this is a sign of Hunter pets taking over as Tanks or anything like that, but it was probably incredibly fun for Durante and his guild. I have no idea where his guild (which is recruiting Healers, apparently) sits on the meter between "Casual" and "Hardcore" but even the most hardcore guilds need to have a little fun sometimes and I think this qualifies.