Frankly, I find this silly at best, and it looks pretty dang disingenuous from where I'm sitting.
That is, it seems quite obvious to me that spells are very different things from augmentable powers. Yes, 3e (uniquely) did put psionic powers on a 1-to-9 level system like spells, but psionics were still different from spells--in several ways.
The spellcaster psion we're going to get in 5.5e is, quite literally, almost entirely identical to a wizard. It's not just "well these things kind of function like spells". They literally are almost exclusively Wizard spells, just with a (very, very slight) bent toward mentalism stuff.
Like, why on earth should a psion get Abi-Dalzim's horrid wilting? Why would they get polymorph? Eyebite? Power word fortify?
Several of these are simply filler to ensure that certain checkboxes are ticked. They have nothing to do with supporting the theme, developing psionic abilities, or exploring the design space. Even some of the brand-new spells are like this, like bleeding darkness!
Yes, psionic abilities--if they are done exactly as they were in 3e--will have some kind of similarity to spells. But if that's the tack you want to take, then Battle Master maneuvers are spells too, because those are discrete powers with clearly defined effects.
Broadening "spell" to mean literally any defined mechanical ability ever sounds like a pretty bad definition of "spell" when we have several characteristics that are specific to "spells" and not shared by other kinds of ability, supernatural or not.
Like, NGL, this feels like openly trying to subvert the [+] thread by saying "well since all abilities are effectively spells anyway, you're wrong for not wanting spells".