Oofta
Legend
You answer your own second question here. For a number of fans of psionics, what that alternate source of magic represents is appealing because it has a different set of thematics and aesthetics than fireball-slinging wizards wielding cosmic powers, pious clerics drawing upon their gods, primal druids wielding nature, and bards singing their magic.
So have a warlock or sorcerer with a different patron.
Unless you come up with an entirely different spell list/system it just becomes a different power source with slightly different fluff.