Before I begin... that survey is going to take forever to fill out. The prudent thing for WotC to do is to break it up into two different surveys, one for Mystics and Orders, and one for Disciplines. I'd rather take two 15ish minute surveys than one 30+ minute survey.

That said... this is what I'm looking at when it's time to fill them out:

1: The Magic / Psionics interaction needs to be nailed down.

There's nothing wrong with psionics being a flavor of magic:

As described in SCAG, the average dweller in the Realms would lump 'Mindmages' in with Sorcerers, Warlocks, and Wizards as practitioners of "the Art" and not worry about the details overmuch.

But we run into a problem: Responding to it. Right now, Counterspell doesn't work on psionics, but Antimagic field does. Dispel magic targets one "creature, object, or magical effect", so it feels like it should work on psionics, since psionics is a magical effect. But also says it effects spells on the target, so it really doesn't. This is reinforced by the March 2016 Sage Advice article, which refers us to Lesser restoration, Greater restoration, and Remove curse for ending non-spell magical effects. However, these three spells are irrelevant to most psionic effects. This leaves us with three feasible options.

The first is to fully integrate psionics into the current magical system. Talents are treated as Cantrips, and Disciplines are treated as spells of 1 to 5 level, depending on how many points (2, 3, 5, 6, & 7 respectively) are spent to activate the power. By doing so Arcane, Divine, and Nature spellcasters (and their players!) can intuitively respond to psionic usage when encountered, and it adds an in-universe reason why Mystics are a rare breed, since it would allow other spellcasters to counter / dispel them with their 7 level slots, and still have 8 and 9 level slots available, an advantage that 15 level Mystics would lack. It's the easiest solution, but it puts a burden on Mystic play.

The second is to reinforce the concept "Psionic disciplines are magical and function similarly to spells" with examples. A Mystic is using Mastery of Air: Wind Form? Treat it as Fly, and now you know how to counter or dispel it. He's using "Mastery of Air: Animate Air? Treat it as *Conjure Air Elemental. In a nutshell, if a power in a Discipline does the same thing as a spell, treat it as a spell. Otherwise, it's a non-spell magical effect. This may be the "holistic" solution, but the amount of verbiage it would take to list all the examples is pretty daunting, so either the system would have to be rebuilt to show that when a Mystic uses Mastery of Air: Wind Stream, he is creating a non-spell magical effect, but when he uses Wind Form, he's casting Fly, or else it should be stated as "Psionic disciplines are magical and function similarly to spells, and are treated *as** spells if they duplicate a spell's results, at the DM's discretion." and just left for each campaign to figure out.

The third is a little bit of added verbiage specifying which spells (like Antimagic Field) work against psionics, and which (like Counterspell & Dispel Magic) don't, and why. This appears to line up with how WotC intends psionics to work in 5 edition, and the addition of a paragraph or two elaborating on it would solve a lot of arguments. However, it makes Mystics dangerous, as their flavor of magic becomes something other magic-users can't really interact with. This, too, may be what WotC intends, and explains their relative rarity, as it's easy to understand why a guild of wizards or a dominant religion would take action to discourage psionic learning, and to stamp out Orders in their area when they are discovered.

2: Psionic usage is completely covert.

"Using a discipline requires no spoken words, gestures, or materials. The power of psionics comes from the mind." If the intent is to make Sorcerers jealous, WotC certainly succeeded. This, too, may be what WotC intends, and adds sorcerers to the aforementioned groups that would be rather uncomfortable with a group of Mystics setting up in their back yard, and could increase tensions between Mystics and pretty much everyone else. But using psionics shouldn't be completely invisible. Contrast the Fire Bolt evocation cantrip to the Energy Beam talent. The former takes both verbal and somatic components, and a mote of fire is hurled through the air. It's pretty obvious that the bearded guy in robes who just chanted and moved his hands as he threw flame at you is trying to hurt you. The latter? Dude's just standing there. Could be anyone. No visible cue who the Mystic is, and no visible cue that an attack even happened. You just get toasted, like an invisible microwave laser gun that doesn't even need to be pointed at you. That's a really good way to get Mystics declared persona non grata by anyone who knows anything about their capabilities, which ties into the in-universe reasons why any organized group may decide that persecuting Orders is a really, really good idea. Again, if that's the intent, all well and good, but it can directly lead to a campaign mirroring Marvel comics, where practitioners of "the Art" could be honored as heroes or feared as villians, but Mystics are treated like mutants, with fear, distrust, and loathing. Much like Tieflings, but redoubled.

Jumping back to 3.5 edition rules, psionics could have a "Display" that indicated usage. Some made noise, some made momentary ectoplasmic slime, some rang like a bell in the minds of nearby creatures, some made smells (Seriously. Feel free to look it up.), and some made visuals. And some made more than one of these, and users had to make a check to suppress them if they wanted to use them covertly. I'm not advocating a return to those systems, but what we have now is covert to the point where it's understandable if other players at the table would say it's unfair. And they'd have a decent justification for saying so.

If that's what WotC wants, then adding a sentence to the above quote to reinforce it, such as: "The power of psionics comes from the mind. This can cause Mystics to be distrusted, at best, by anyone aware of their capabilities." or the like. Otherwise, using psionics without words, gestures, or materials is fine, but there needs to be some indication of their manifestation.

3: Psychic Assault outshines Illithids.

Psionic Blast, Psychic Blast, & Psychic Crush are problematic when compared with Mind Flayers. Let's look at the Illithid Mind Blast:

The mind flayer magically emits psychic energy in a 60-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 22 (4d8 + 4) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success

So it gets to use it once, and then has a 33% chance of getting to use it on subsequent turns. Whereas a Mystic can single-target using Psionic Blast without a save, or gets a Psychic Blast that does either 36 (8d8) or 45 (10d8) damage? And where saving against the Illithid will prevent all damage, whereas saving against the Mystic only prevents half of it? The Illithid's Mind Blast should be a thing that strikes fear into the heart of any adventurer. Compared to what a Mystic can do... is the Mystic's ability to do more damage really balanced by the lack of a stun, since a Mystic can invoke Psychic Blast four times in four turns, whereas the odds are that an Illithid's only able to invoke a Mind Blast twice in the same amount of time?

And then there's Psychic Crush, which as written would strike fear into the heart of any Illithid, because it's everything Mind Blast is, but better in almost every way.

Yes, adventurers are the heroes of our stories. But should the Psychic Assault Discipline outshine the Illithid like this? Or are we going to see a variant, like the Mind Flayer Arcanist, that gives us a Mind Flayer who is a 10 level Mystic in the same light that Arcanists are 10 level spellcasters?

4: Nitpicks.

• Avatars have 8 Disciplines. The Awakened have 9. Immortals have 10. Nomads have 5. Wu Jen have 8. That's a really lopsided curve. The Immortals could stand to lose two of their Disciplines. The Nomads could stand to gain two. That gives us a spread of 8 / 9 / 8 / 7 / 8. Which isn't perfect, but it's better than what we have now.

• Diminution and Giant Growth aren't exactly concepts that come to mind when you think of a mind-based magic. Those two extra Disciplines that Immortals have? Here you go. You can simply remove both Disciplines completely, and the Immortals would still be an extremely potent Order. Sorry, Pym fans.

• Along the same line, Celerity seems to be just as easy a fit for Nomads as it is Immortals. If not better.

• What should the Nomads get? Powers relating to travel. Some sort of "dimensional anchor" effect, perhaps, or a individual version of Plane Shift, or revisiting 3.5 edition's Baleful Teleport, which could cause psychic damage to the target. Or powers relating to the other planes, such as conjuration or banishment.

• And while we're on the subject, if ANY class should get access to some version of Astral Projection, shouldn't it be the Mystic?

• Mastery of Light and Darkness: Shadow Beasts is a problem. The user is summoning two chaotic evil undead creatures that obey your commands. But if you actually tell your shadows to use their Strength Drain in combat, you run the risk of it killing their opponent, and "if a non-evil humanoid dies from this attack, a new shadow rises from the corpse 1d4 hours later" So now the Mystic is permanently creating new chaotic evil undead creatures that he has no control over whatsoever. Summoning shadowy creatures is cool. We've seen this in the Shadow Sorcerer from the Light, Dark, Underdark! UA release. Summoning a pair of actual shadows? Problematic, at best. At worse, it lets an evil Mystic show up in a town, summon a pair of shadows, and tell them to start killing people. Sure, they'll go away after an hour. And a short time after that, all the good and neutral townsfolk they killed will spawn shadows. Who will kill more people. And thus spawn more shadows. With a single invocation of the power, our Mystic has now started an undead plague. That's a really, really good way to get Orders put on an "Execute on sight" list by any power group, whether religious or secular, who think that all psionic users can (and will) use their powers like that.

The current rules for Mystics and Psionics are obviously a labor of love by the WotC team. They should be commended for all the hard work and dedication they've obviously poured into the project. But, like all UA material, they can be further refined. Addressing these issues would go a long, long way in doing so, while still keeping the system fun for everyone in the game.