I had a bit of a curious weekend.
I did a few instances with my daughter.
Then she persuaded me that the headless horseman fight was so short that nobody was going to kick me for being undergeared or my pathetic dps.
So I queued up and did it. Initially with my hunter as I felt he had the most chance of not being an embarrassment. It went ok and he got a nice upgrade.
So I took another 6 85s through it (all DPS - I left out the tanks as I didn't dare attempt to tank it). Results varied enormously.
They are all around the 320 iLvl mark having dinged 85 and some of them finished the quest sequence in TH. Pretty much all blue from quest rewards and crafted gear. Not fully enchanted/ gemmed since their gear is going to change - hopefully to something with gem slots
What I got out of it in terms of peak dps was:-
BM Hunter 10k
Arms Warrior 8k
Frost DK 8k
Enhancement Shaman 7k
Combat Rogue 6.5k
Demonology Warlock 4.5k
All pretty horrible from what I read here, but particularly upset by the poor showing of my warlock. There didn't seem much I could do to improve. Dots were up, Meta was used as was Demonic Empowerment. Possible reasons are lack of haste - those nukes take forever - or lack of spellpower.
So a bit of a mixed experience. But at least a pointer to what needs to get better. Probably the next step is to grind some rep for upgrades.