Different system, yes. 'Not magic?' not so clear. Magic & psionics interacted in 1e, yes. But so did magic and gamma world mutations and technology, in the 1e DMG.
Small cavaet: never used psionics under 1e (since I never played 1e, just read the books). My play experience is with 2e and on, so I'll keep to them.
Now, starting with the Complete Psionics Handbook, I can tell you with certainty magic interacted with psionics poorly. Detect Magic did NOT detect psionic powers. Dispel Magic didn't dispel psionic powers. You could use psionics in anti-magic, dead magic, and so on (one of the reasons Dark Sun gave used it prominently). Psionic powers required no verbal or somatic components, you could even use them while bound or stunned (as long as you could take "purely mental actions"). Psionics had no level (which was why they were sometimes gamebreaking; disintergrate at level 6?) required ability checks to activate (and could potentially backfire if you rolled poorly enough, I'll have to tell you about Ivan the Sentient Psionic Bridge later). Psionics even had a strange (and obtuse) form of combat using attack and defense mechanisms. They were "magic" in the sense that they were a non-mundane, but they were not MAGIC as D&D defined it.
Backwards. 4e gave Psionics it's own 'Source,' making it definitively different from Arcane, just as, say, Martial was. 3e explicitly gave you the magic/not-magic choice, for the first time. 4e went the other way, it was the only edition that took Psionics, Divine, Primal, &c and made them all distinct Sources.
I don't expect 5e to take the 4e course and make Psionics distinct from magic, since it's abandoned formal Sources, and, because 33 of 38 sub-classes already use spells in one way or another. [/QUOTE]
:facepalm:
I just explained why 2e psionics was completely different than 2e magic. Shall I do the same for 3e now? How you couldn't make a "magical" item out of psionics (but instead had their own special item creation feats)? That powers didn't scale with level but required power points to augment them? (A precursor to 5e's high slot system). That they used "Psionic Focus" as a mechanic to keep/expend psionic power? That they lacked Cantrips or 0-level powers?
Even in 3e, psionics was a very different beast than straight magic. 4e didn't invent powersources, you know.
Or 'mind magic,' yes. Exactly. Psionics is a supernatural power, placed in a fantasy setting, what else is going to be but 'magic' in some sense. Two of three Monk sub-classes use spells for their Ki powers, why wouldn't a Psionic sub-class (or full class) also leverage the tremendous amount of space the PH1 devoted to spells?
Most of those are things already done by spells. Sub-classes can add to spell lists, so filling out the few that aren't isn't a problem. Likewise, adding a feature that eschews certain components wouldn't be out of line.
The Player's Handbook is done and dusted. I never expected psionics to be in it. The monk needed to be. I accept that giving them "spells" was a good shorthand to fit more stuff in the PHB. But we're not talking PHB anymore; the skies the bloody limit. They can do psionics in anything form a UA to a hardbound tome, they can put out as many unique abilities as they want.
By the same token, you could have cut the Sorcerer, Warlock, EK, & AT. Wizard sub-classes could have covered the gamut, and multi-classing the two 1/3rd casters.
But that's clearly not the standard 5e is using.
Its hard to know what standard they are using; they've released the PHB and a single 25 page PDF of player stuff. (And a couple UAs, which are barely more than playtest). However, despite having spells in the book, they found the ability to put in Invocations and Superiority Dice as subsystems as well; I doubt 5e is new-system averse (and it clearly doesn't mind optional rules).
While I empathize with that point, genuinely, I just don't think WotC has shown an enthusiasm for that approach. Rather than give Monks their long list of Ki powers, Barbarians Totems, and so forth, they gave everyone who did anything supernatural spells. It's an efficient approach, letting them do the most with the least design resources and without the complication of wildly different sub-systems. But, I agree that it is disappointing in some cases. Psionics may turn out to be one of them.
OTOH, I'm afraid "go big or don't bother" is a lot more likely to get us "don't bother."
Then don't use them if you don't like them. But don't half-ass them for use who DO like them. A psionic sorcerer is a lazy, half-ass way of doing psionics, any person on this board could make one and put it in the database and claim "psionics for 5e is done." Let psionics be for those who want to use it; make your own sorcerer subclass if you don't.
Better something than nothing.
I'd rather nothing than crap.