Well the warning for Dancing Plague Extreme is the "Extreme". Those aren't something you casually beat blind.

And as for Stone Vigil hard, you got 4 cannons in the room where you normally never have cannons in a fight, and your normal attacks do little to no damage. At that point, anyone who is paying attention would think "Hmm, maybe I use these cannons", but unfortunately sometimes you can't fix players who don't want to pay attention. That's not the content's fault, that's the players.