Here is an idea to solve the complete lack of diversity of useful end game stances for melee monks.
The problem is that Monk PRR is only available in Earth Stance, maxing out at 45, and requiring an expensive T4 twist. This solution would free up PRR from earth stance entirely and would allow Earth Stance to focus more on tanking requirements.
Here goes:
Monks would aquire through level progression, analogous to the unarmored movement speed bonus, a percentage increase to PRR based on armor class.
This would only apply while being centered and being unarmed or wielding melee weapons, and cap at 50 PRR:
Lvl 3: 5%
Lvl 6: 10%
Lvl 9: 15%
Lvl 12: 20%
Lvl 15: 25%
Lvl 18: 30%
So a 12 Monk build with 150 AC would naturally aquire 30 PRR, the equivalent of Earth Stance with the Iron Skin enhancements.
An 18 Monk build with the same 150 AC would aquire 45 PRR (The current max Earth Stance PRR). Regardless of stance/enhancements and without the T4 twist.
We would then need to remove PRR from Earth Stance, Iron Skin and the T4 twist Standing with Stone. These PRR bonuses could simply be turned into AC or health bonuses.
Earth Stance would be configured to provide a maxmimum of 15% health instead of PRR. This would give monks a source of percentage health that is currently only available in Unyielding Sentinel, whereas all other tanks can double up these percentages through Fighter/Pal stances. Finally the increased crtical multiplier would be moved to Fire Stance, as the health percentage with critical multiplier would only serve to make Earth Stance the only viable stance once again.
Iron Skin would be: 3/6/10 AC or 1/3/5% health, applies to all stances, maybe a multiselector here, AC or health. This would give other stances a small source of percentage health outside of Earth Stance.
Standing with Stone should be more powerful than Iron Skin, so I would change it to: 5/10/15 AC and 10/20/30 health (replacing the current 15 PRR and 15 health).
Changing these to AC options provides synergy with the new PRR system and helps monks and monk splashes achieve better PRR based on smaller percentages.
So to sum up an 18 Monk, melee (150 AC), with Iron Skin:
Fire Stance: 45 PRR, 5% Health, Crit Multiplier and Ki.
Wind Stance: 45 PRR, 5% Health, Speed and Double Strike.
Water Stance: 45 PRR, 5% Health, Saves and Dodge.
Earth Stance: 45 PRR, 20% Health, Threat and AC.
Finally, I would change the Grandmaster of Flowers stance modifiers to be multi-selectors. Making each of the stance modifiers avaialable at T2 (choice of all 4 at T2 and progressing upwards). This would further promote stance diversity through an equal twist cost. Why should Fire Stance monks be locked out of improving their preferred stance, and Earth Stance monks punished by a T4 twist cost?
This would open up Fire and Wind Stance to true DPS builds, solid Earth tank builds, and super resilient Water Stance options.
Seems perfect to me - thoughts?