The whole romp through Karazhan give me the impression they didn't test ANY of the heroics. Like, heroic Nightbane I was expecting just him to start at 10 mana, not both of us. Nope, instead he has some...I don't even fucking remember. Picked one of my control ladder decks and destroyed him.
With how easy Heroic Karazhan has been, that reminded my that I still had a few in BRM and all of LOE to do. First off, fuck heroic chromaggus. BRM and Naxx were maybe slightly overtuned overall, but chromaggus specifically was fucking stupid.
I feel Heroic LoE had the exact right amount of challenge. Figure out how to build your deck, tweak it over a few tries, win. Slitherspear was the only real hard one. Perhaps my own fault because I really wanted to beat him with a mill deck(and did).