For our 10th-level playtest we had enough time to complete one CR 13 encounter. We had a Spiritualist, Medium, Psychic, and Kineticist at the table. I will be writing for the Psychic.
I’ll start with my conclusion: I don’t feel compelled to play a psychic over a sorcerer, the class that seems to have the most in common with the Psychic. Even taking precautions by having options for use against creatures that are resistant or immune to mind-affecting effects isn’t enough. The class is hard countered by some of the most challenging combats in the game.
The spell list is limited and easy to distill down to a short list of best spells known. The rest of it functions as scroll and wand fodder. Here’s the disappointing part: your scrolls and wands are going to cost more than for a sorcerer. Why? Because a psychic cannot cast arcane or divine spells and there isn’t a full caster psyionic class with spell progression like a wizard (i.e 2nd-level spells at 3rd character level and so on). That said, there are some immediate action spells available only to the psychic which could prove to be a thematic boon to your companions. I’m on the fence about them though.
Mind-affecting effects are unreliable against the most dangerous opponents. These are some of the best thematic options for the psychic. Everything else a wizard or sorcerer can do just as well. Those constructs, oozes, undead, plants, and vermin (without will of the dead) are going to be frustrating. Plenty of high CR creatures will have protection from evil spells active, or the equivalent.
The phrenic amplifications are very disappointing. Out of the six options only 3 are even remotely worth considering. That’s not saying much either. Overpowering Mind is fine, but its not fun. A +1 or +2 is not a defining power. Give me something exciting. Will of the Dead is a little better as I can now effect undead with my best spells! Except that I have to expend a lot of my resources on a single casting. Hey, at least that phrenic pool isn’t going to much use anyway. It’s for this reason that I personally chose to keep the ability score keyed to my character’s phrenic pool (Wisdom) at a 10.
The disciplines are okay, and I chose one of the worst, yet most thematic for a supposed Pathfinder: discipline of lore. Few casters that select spells known are going to want to choose augury, blood biography, contact other plane, or so on. The automatic writing ability doesn’t even allow for regaining of phrenic pool as it is a supernatural ability. Discipline of pain is one of the better options because the character gets automatic breathe of life. However, it feels half-baked that a discipline based around pain would have one of the most potent healing abilities.
My suggestion, which is probably too late at this point: Compare the psychic to a bard, not a sorcerer. Give them the cool psychic only spells (adjusted for fewer spell levels) and use the lost spell casting to allow them thematic choice. If any class or archetype can use the power of their mind to do nearly impossible things, it should be the psychic. I’d actually like to see them able to select spells known similar to an arcanist. Or have them prepare psychic spells similar to a warpriest. A psychic’s mind should be flexible and unique.
You can see my rough draft character sheet here.
It's been nearly 9 months since I've played a psychic and I feel compelled to write a follow-up to the above post for those who might see it. I absolutely LOVE the final release of this class combined with the other options available in Occult Adventures. I'm now enthusiastically playing a psychic in PFS, enjoying much of what I had before, but now with just enough extra stuff to make the class exciting and distinct. I encourage everyone to take a closer look post playtest.