I rarely cover Unearthed Arcana content. The primary reason for this is that I simply don’t have the time. UA content makes it to final publication less than half of the time, and my crystal bar isn’t clear enough to predict what’s going to make it to print, so I’d rather spend that time on stuff that’s already in books and that I know everyone can actually use.
The Mystic is a weird case. WotC tried a few times to get psionics right before we got the psionic subclasses in Tasha’s Cauldron of Everything, and the most iconic example was the Mystic. It was the first full class that we saw outside of the core rules (yes, it predates the Artificer), and a lot of people are very excited about the Mystic several years later. I occasionally get requests from people asking me to write a class handbook for the Mystic.
To reiterate: I will not cover the 5e Mystic class in its current form.
Now I’d like to explain why.
For people who have not read the Mystic UA article: it’s 28 pages and includes six subclasses. That alone is a terrifying prospect as a playtest document. I believe that’s a larger page count than any other class except possibly the Cleric (there are lot of domains) if you total up the page count across every published source book. This thing is massive. And goodness, it is a mess.
The Mystic is riddled with abuse cases. The class is way too complicated, having more build decision points than the Warlock and more decision points during play than any existing character because of the way psionics and psi points work. Some features are just outright numerically unfair (you can get a cantrip-equivalent feature which is just Mind Spike with d10 damage dice instead of d6), and many allow unfair combinations that immediately outshine other characters.
This thing is not balanced. It’s not even close. I can fix Peace Domain with some patches and house rules, but the Mystic is too far gone. If I tried to patch it, it would be more patch than content. We’re talking a Ship of Theseus scenario here.
So you might reasonably think “Okay, what if I do an all-mystic party and just lean into the imbalance?”. That might work. There are a couple things in the class that will make you regret that like Order of the Avatar’s Avatar of Healing which provides an ability similar to Life Domain’s Disciple of Life feature, except that it also applies when any of the Mystic’s nearby allies regain hp from a Psionic Discipline, so basically everyone in the party gets Disciple of Life.
I can’t recommend playing the Mystic. I certainly don’t recommend allowing it at your table.
The Mystic is an actual mess, I would sooner recommend someone seek out a homebrew psionic class. I would personally recommend KibblesTasty’s Psion, it’s free and pretty comparable to something like a Sorcerer. Most of his stuff is pretty high quality, aside from all the typos.
I played a mystic once, in a one-shot, two or three session adventure wherein the GM was trying to kill us, and we were deliberately making use of the most unbalanced combinations possible. It was a lot of work and a whole lot of fun.
If anyone does want a mystic guide, there was one on Giant in the Playground: https://forums.giantitp.com/showthread.php?542539-Mind-Over-Matter-A-Guide-to-the-5e-Mystic
There are nine hells of a lot of weird interactions and odd bonuses lying around. For example, the Mastery of Force gives 14+Dex AC, you can focus on one of the Immortal disciplines for another +1 and also have a longer term Shield of Faith style bonus from that same discipline, which is an excellent AC for someone who might not be a frontliner.
I am totally fine with your decision. I would request that you do the UA Ranger (since it’s probably one of the most used UA out there), but I imagine all you have to say is, “It’s better than PHB Ranger.” I would still like to hear your thoughts. Maybe a 5 minute blurb on your podcast, which is excellent.
I’ll give that one some thought. A side-by-side with the post-Tasha’s Ranger would be interesting.
I only allow 1 person to play any play test in my games and this class was the it, it is so broken and was having to come up with so many fixes to the class to make it fair not just for me but the other party members, the player playing would regularly get mad about the changes but i had to keep telling them that no other class gets to do this without some kind of balance, its the first class ive ever come across i just hate and will not allow to be used again at my table