Level 80s who single target groups of mobs

[SturmChurro]

Here is how you fix it : extend the trust system to every single dungeon in the game.
For sure you'd still get a few bad apples but I think that a large portion of the people who show no desire for self-improvement are probably not interested in the MMO aspect of the game.

They added the hall of the novice to teach the basics, and even then people were not doing the basics.
If people don't want to learn, they'll never learn, no matter how much training they have.
That's also why even the easy solo instances have a 'very easy' difficulty option now. People don't even want to try learning the patterns of those easy encounters.
If they want to learn, they have plenty of tools at their disposal (Google/Reddit/forums/in-game chat/skill tooltips...)

This is an mmorpg. I think the game just probably isn't for them. There are plenty of single player games for them out there! No reason to waste resources on more trusts, to that extent.