So, how do we make this move better? Honesty, the simple method would be to make it more like its PVP counterpart. For PVP, after using Riddle of Earth, after losing 50% or more HP, it decreases damage taken by 10% and increases damage dealt by 10% (both Riddle of Earth and Earth's Reply buffs last 10 seconds). For PVE content, just switch the "losing 50% or more HP" to "getting hit" part and give it the damage related buffs. Better yet, you can get rid of the damage reduction part entirely and just keep the damage dealt increase, as well as increase the amount by 5% or the duration for 5 seconds (or even both). This would make it similar to SAM's Third Eye, but would definitely give it frequent use. Only downside to doing this is that a player would need to keep track of their buff timer and weave in Fist of Fire in order to not let their damage drop, but that's something a more skilled player would be concerned about and wouldn't really make the class harder to play.

Of course, if making Riddle of Earth a defensive-offensive buff would disrupt the balance of DPS too much and it'd be better to keep it as a defensive buff, then that's what it should actually do when faced with an attack that can one-shot you. So, with that said, if we're going that route, the best course of action would be to give the extra damage reduction, maybe even increase it by 5-10% more, right when the move is used, reduce the buff duration to 10-15 seconds, and to double, maybe even triple, the recast timer. Since there are only a handful of occasions when a high-level player will use RoE for the GL refresh, making it a one-time life saving move would be very useful in that it could save a lot of pulls that result in a wipe due to one death. The only downside I can see to this is for monks to then abuse the move to ignore certain mechanics and purposely get hit in order to keep uptime on a boss (admittedly, even I'd do that as well).

So between the two options that could likely disrupt the DPS balance, the offensive option is probably the better option since the defensive option would probably be more game-breaking, though it'd be useful all the same.

That's it for my opinions on Riddle of Earth. Be sure to check out my thoughts on Arm of the Destroyer and One-Ilm Punch!