Granted I've only played WoW but they don't generally give tutorials on how to beat the dungeons. Deadmines comes to mind where you have to have 1 guy get in the Robot and hold off the adds while everyone else takes out the boss. There's no tutorial for this, people had to figure it out.
Deadmines taught you how to use the robot on the trash before the boss.
Theres a difference between handing someone an instruction manual and easing them into a new mechanic.