The only thing I will admit from the other side of this... "debate" is that RM is a huge difficulty spike over the other dungeons and trials.

You actually get punished really hard for your mistakes- instant death- on something such as tidal wave. Tidal wave, only a few seconds into the fight, is far FAR from "intuitive" and something we really havent seen before. Your first time in?

"what's this water puddle outside the ring? am I supposed to run to it? is it going to explode and I stay away from i- oh, I'm dead because I got pushed off."

Diamond dust is very unforgiving and unintuitive in the same way. It isn't new persay, but just seeing "Diamond Dust" isnt going to tell you the area is frozen like it is for several seconds, and depending on if the tail has destroyed the arens, you get outright killed by diamond dust as well without much warning.

Those 2 mechanics aside, The trial doesnt throw too much at you that isnt intuitive, seen before, or even really punishing to fail... aside from maybe the add phase for tanks(the amount of times ive been slapped with death sentence even with diversion is staggering). On top of that, If RM has an enrage, Ive never seen it. The trial is very VERY forgiving in that regard.

All that said, I'm not really sure how they -could- nerf it? the major mechanics that kill everyone are due -mostly- to falling off than the incoming damage. They could lower the damage, but I'm sure RM would still have people up in arms because of tidal wave, because of diamond dust, because of the charge, because of the tornado...