The thing I found that made this fight really easy is being able to cast viral reverse damage shields on the mobs (like cleric spell Blood Of The Unsullied Rk. III). The mites have such little hitpoints that they die within seconds. When the waves come, they get infected with the damage shield and kill themselves, and you can just sit back and focus on DPSing Bloodfeaster. You can also use AE nukes in conjunction with the viral shield to slaughter them faster.
Me and a friend do this fight occasionally. Group is made up of 85 Bard with AE slow ready, 85 shaman with AE slow ready and 85 zerker with 2 t5 cleric mercs and a t5 tank merc. The tank is merely a distraction at the start, buying you enough time to burn the hell out of the Ukun named, both clerics and the shaman spam healing anything that takes damage, usually one of the clerics ends up with most of hte aggro. Kill the Ukun in about 50 seconds, then while under disc, the zerker will rampage the crowd. The adds have so little hp they almost all die instantly, except for a very manageable few. Have done this 3-4 times without even getting a merc killed.
Ok so I have been wipped by this mob a few times. Finally learned my lesson and got an 85 Chanter with AE mez to step in and mez all of the annoying mites. Once they were mezzed the Ukon went down very easy. As for the mites I wouldnt waste time killing them. Just loot up and succor to front of zone. Hope this helps.
So... I had the bright idea that I would try this guy with just me, my pet and my merc... opened the door, moved to a corner so I'd be able to cast... I lasted MAYBE 10 seconds TOPS. I only got in 4 rounds of attacks before I died, didn't get a single spell off. Merc died almost instantly after me.
Most hits were in the 330-360 range, did get hit once for 1100. The fight wasn't long enough for me to really try anything. Couldn't tell how fast things were attacking because there were just soooo many of them.