Depends which one you went too. Slave Pens and Mechanar were extremely easy, Durnholde and Black Morass were intermediate, Hellfire's required specific class combinations for CC, and all of the Auchindouns would take you three hours of wiping to get to the end.
TBC heroics were 100% class role specific. You weren't clearing Heroics with a DPS Warrior, Enhancement or Elemental Shamans, or even a Feral Druid.