I'm not 100% sure where we are supposed to write in game suggestions but this is a good place as any I guess.

I feel currently that most dungeons are simply not punishing enough if people stand in red markers and other bad stuff. As a healer I often see other players simply ignoring mechanics cuz I can just simply heal+dispel them as necessary which is very annoying. Not cuz its hard but it destroys the feel of a fight. This is most commonly seen in a light party, which in my opinion is a very bad thing as I consider light party in one way to be a trial for bigger challenges.

My suggestion would be to add a constant, stacking, non dispellable effect if you get hit by a mechanic you are supposed to dodge. 5% less potency to damage and healing and also increased damage taken, making these effects eventually oneshot the player. Make this an infinite effect lasting till the player either dies or exits the dungeon