Now I'm going to say something - the biggest problem in heroics isn't players who don't know what they're doing. It's players who do. Specifically, it's skilled and geared players who massively, massively out-gear said heroics and want to ignore the mechanics and chain pull every mob in the place, players who are completely inconsiderate of the other players in their group. Players who are skilled, but who let their fevered egocentric natures run wild, hurling insults at lesser geared players for 'not keeping up.' Players who make the dungeon an unpleasant festival of wipes because they refuse to understand that some of the people in the dungeon are only just geared enough to be there, and can't heal through thirty mobs hitting them at once or kill those thirty mobs fast enough.
It's players who have a really well geared main, but come to the Scarlet Monastery Cathedral on their brand new monk and refuse to understand that they're not nearly as powerful now. It's not skill, it's attitude.