On a side note, we finally downed Thorim 25 this week after a ton of wipes. Some things that really helped in the arena:

1 Tank (Paladin) on Darkrune Champions and 2 DPS dedicated to getting them down. I think at most we had 2 Champions running around.
1 Tank (Paladin) dedicated to Evokers with the rest of arena DPS on them.
1 Priest spamming dispel.

I really think having dedicated teams in the arena made the difference, as we were able to keep from getting overrun until Thorim came down.

Hallway group had a bear tank and that seems to work well.

Ambrosyne walked out of our for-lulz run with a firey halo and a pretty dress. She showed up to the gig in full t2, because I miss that set so. Damn. Much. :D WTB that armor designer back, plox.

I also yelled LOOT THE DOGS over vent just because I could.