I just did a rework of the Tranquility Monk that balances things a bit better. Feedback is welcome!
Healing Hands
Your mystical touch can heal wounds. Starting at 3rd level, you have a pool of martial dice (d4s at 3rd level, d6s at 5th level, d8s at 11th level and d10s at 17th level) that you spend to fuel this healing. The number of dice in the pool equals your Wisdom modifier (minimum of one).
As an action, you can heal one creature you are touching, spending dice from the pool. Roll the dice you spend, add them together, and restore a number of hit points equal to the total.
Instead of healing the creature, you can expend one die from your pool of healing to cure the target of one disease or neutralize one poison affecting it. You can cure multiple diseases and neutralize multiple poisons with a single use of Healing Hands, expending dice separately for each one.
When you use your Flurry of Blows, you can replace one of the unarmed strikes with a use of this feature.
Your pool regains all expended dice when you finish a short or long rest.
This feature has no effect on undead and constructs.
Wise Counsel
At 3rd level, you become an authority of wisdom. You can use Wisdom as your ability score for Persuasion checks instead of Charisma.
You also gain proficiency in the Persuasion skill.
Zone of Peace
Starting at 6th level, you can become an island of calm in even the most chaotic of situations. As a reaction, when a creature within 30 feet of you is targeted by an attack or a harmful spell, or makes an attack or casts a harmful spell, you can expend 3 ki points to create a Zone of Peace in a radius of 30 feet centered on you. The triggering attack or spell is affected.
The DC equals 8 + your proficiency bonus + your Wisdom modifier.
For 1 minute, any creature who targets the warded area with an attack or a spell that deals damage or causes a saving throw must first make a Wisdom saving throw. On a failed save, the creature must choose a new target or lose the attack or spell. This includes moving area effects to not overlap with the warded area, such as the explosion of a fireball.
In addition, any creature within the warded area must first make a Wisdom saving throw to make an attack or cast a spell that deals damage or causes a saving throw, even if they are targeting someone outside of the warded area.
You can end this effect before it expires.
Once you use this ability, you can’t use it again until you finish a long rest.
Balanced Healer
Beginning at 11th level, using Healing Hands on others heals you as well. When healing someone else with the Healing Hands feature, you regain an additional half of the rolled hit points.
Anger of a Gentle Soul
At 17th level,you gain the ability to visit vengeance on someone who harms others. If you see a creature reduce another creature's hit points, you can use your reaction to grant yourself advantage on attack rolls against the aggressor and attacks that hit the aggressor are critical hits. This lasts until the end of your next turn.
Once you use this ability, you can’t use it again until you finish a short or long rest.