The weave is only one interpretation of the interface.
Like I said.
If Psionics or Primal or Incarnium are spells, then wizards can add them to their books.
Then a cleric can dip into a level of psion and toss their 1st level psionic spell in a 9th level loss.
The new Fey/Shadow feats that let you know any 1st level spell of certain school. ANY SPELL FROM ANY CLASS of those schools.
Coffeelocks.
Youll have to add rules to make the lore start looking screwy and weird.
So... nothing new.
Wizards can add Divine spells into their books, if they share them in their class list. And Wizards already have Psionic abilities as spells (telekinesis and multiple versions of telekinesis at that, two different telepathies, the ability to see the future, Detect Thoughts, Suggestion, Charm Person, ect)
A wizard can dip one level of cleric and throw their 1st level cleric spell as a 9th level loss. Heck, they could go two levels of Paladin and throw a 9th level divine Smite.
The other two things stay those things.
You aren't pointing out new problems with the lore. Just old ones that you don't like with this new coat of paint.
I didn't miss it. I answered it with my response. Magic and not magic have a distinction of their own. It doesn't take someone to make it useful.
So, you can explain how the Succubus's Charm ability isn't magic? How about a Beholder's Eye Rays?
The distinction between magic and not magic is just as useful. If psionics are supernatural, but not magic, then detect magic and dispel magic won't work against psionics. Other things will be different as well. It does not take a person to view those as distinct. They are distinct on their own merits.
Cool. You magic levitation can be dispelled, but if psionics is supernatural, but not magical, mine can't be.
So, the real thing you seem to be interested in then, is removing counter play. You want a set of abilities that cannot be countered or dispelled within the current framework.
Because that is a difference you are adding. Nothing about Psionics would require us to say that it isn't fully compatible with magic. But, you want the ability to avoid being dispelled. To avoid being countered. To scy through a guards and wards set up. To read the mind of a person under Mind Blank.
This is after all, the first distinction you want to point out. Which indicates to me it is something very important to you, and to me.... that is just not something I want in the game.
You actually believe that?
Do I actually believe that I found a magical spell called Levitation, which levitates an object or person, therefore making "levitating something" a magical spell in the game? Yes. I can even post a link to the DnD Beyond page of it.
Do I believe that this then proves your statement "Not true. It's supernatural, but not necessarily magic. " at least partially wrong in response to Crimon's "Being able to levitate objects or shoot mind bullets is magic. Period."? Also yes.
Because Levitating objects is something done via magic.... a lot. In fact it is one of the most common signs of "person who knows magic" to have them move something via magic, without touching it. Or, to move it with their mind or a gesture. And there is no indication that such effects are not in fact magic.
And, "mind bullets" still accurately describes Mind Spike, so I believe that I was correct to say that was a magical spell effect too. Since it is.
Who said weave?
I said 5e has an assumption of a shared interface.
Because 5e no longer seperates spells by classes and type. They are just spells and every class interfaces with spells in a universal sense.
Scrolls
Spellbooks
Domains
Multiclassing
Flexible casting
Divine smite/Primeval Awareness
Spell granting feats
It's just spells and slots. Everyone uses them.and interfaces with them somewhere down the line.
Blame 5e for making the game more user friendly, less restrictive, and easier to learn.
Okay... but where do have a rule stating that is because of a unique, third element that acts as an interface between people and magic and not just... how people interact with magic.
Music can be created by the human voice. That music can be written down. That music can be presented in different styles of singing. Training in one type of singing can make you far better at learning and working within a different style of singing.
And animals can use the same interaction to make far different, and sometimes far more powerful sounds, not because they have a different third element interface, but because their bodies are designed differently and so they can interact with sound and music differently. Even though they are interacting in a similar universal sense.
So, nothing you listed points to an "interface" between people and magic. This could all be just how magic works.