I didn't read all of posts in this thread, but I agree with the OP.

I've had plenty of dungeons where the "mentor" was not acting like a mentor at all. I've had some who were very rude. Others who begin to pull the boss before the newcomer has a chance to view the storyline cutscene. Others who kick a player when they don't perform well, instead of teaching them how to do it.

I've had mentor tanks who never use a single cooldown during the entire run.

I've had mentor DPS who decide the tank isn't moving fast enough, pull more and more mobs, and when the tank can't hold all of the threat or dies, get upset.

In fact, I have never once been in a dungeon where I saw a mentor give a single piece of useful, kind advice to another player.

I am certain there are some good mentors out there and I don't know what goes on the Novice network, but whenever I am in a dungeon and someone has the crown next to their name, I am immediately put on alert. Not all of the ones I am in a dungeon with are bad by any means, but some of them are and they actions made me suspicious of the other ones. Call it one bad apple spoiling the barrel.

The people who have helped me most in this game are people who are not mentors.