Parmandur
Book-Friend, he/him
I applaud their continued attempts to get something that feels "right enough" for their audience (wish they could show that kind of devotion to the Ranger, but c'est la vie).
My gut tells me a psionic class, if they decide to go back to that concept, would be something like a bard/warlock mix (conceptually). Not literally a mish mash, but a limited pool of spell casting slots but with nifty Invocation-like things...and something like the Inspiration die (not the talent die...interesting though it was, it just felt backwards...struck me as something more at home in the oddball collection of 2e mechanics). You'd have its psionic powers (or spells) with very limited slots, like a warlock, but a psionic type of Invocation/Inspiration type deal (where some might use a die, some might not) rather than be similar to warlock invocations which, for the most part, are just at-will spell options (obviously not all of course).
Or perhaps that's just a psionic warlock subclass. I don't envy WotC this mental pickle.
To be clear about the Ranger versus these options, the Ranger and every Ranger Subclass is already well over the approval rating they are shooting for here: if they got a Psionic option that was as well liked as the Beastmaster, they would publish it!