That's a a tough little quest on elite...
15 or so of those spell-resistant duergar in each of the main fight rooms (4 big fights)
We had a heck of a time in there last night on elite (level 12 quest, characters were levels 11-14, fairly balanced PUG).
Even with the first time 50% elite bonus, I only got 3000 exp... Please increase that.. That quest (12th level on elite) was much harder than any of the Gianthold quests on normal (13th level on normal).
Oh and thanks for mixing in Rust Monsters with the duergar... You made me break my Greater Bane Dwarf dagger (I lagged out and apparently hit the Rust Monster standing nearby with it).
Seriously though (I'm not really complaining about the rust monsters), increase the exp....
Actually, I'd highly recommend someone going through ALL the quests and re-examining exp and loot... There are many many quests where this needs to be rebalanced.
*******Spoiler Alert*************
Bravo on the hidden pit by the way...