Heroics then required CC, strategy, interrupt assignments, even dps thresholds. These things failed miserably in pugs where people just wanted to bounce around in mindless happy fun time and pretend standing in fire was a dps gain and dispels and interrupts were not even worth hotkeying. As a result the forums flooded with complaints about how difficult and time consuming heroic dungeons were and blizzard responded by going back to the Wrath model. Dungeons arent really meant to be meaningful content, they are a vehicle to get valors and gear up to go raid. Personally I'm fine with this, I'd rather things be easy for the weakest link in the group then wipe over and over cause the tank, healer and a DPS didn't get standing in "Harvest" on Foe Reaper, with its brutal looking animation, will kill you...I sadly can't comment on how heroics were at the start of Cata because i started playing again at the end of Cata after leaving at the end of Wrath.