Yaarel
🇮🇱 🇺🇦 He-Mage
That's certainly an interesting take on it, one that I hadn't thought of before.
That being said, I think they should let psionics be whatever the DM wants it to be, not tied to a specific cosmology/setting. For example, I'd probably still utilize psionics as a distinct force from arcane and divine magic and emphasize it's more "sci-fi" overtones.
I agree that all classes need to be conceived and written in ways that are setting neutral.
We know that most DMs create their own Homebrew settings that are interesting to them and their adventurers. Classes must accommodate and facilitate this creativity.
At the same time, it helps D&D players to illustrate a concrete example of how a class can fit within the context of a particular world setting. A separate textbox can explain how the class and its magical powers and social organizations interacts with the rest of the cosmos. So, the textbox can explain how Psion functions as part of Divine ‘Force’, similar to how the textbox explains how the Bard (a healer) functions as part of the Arcane ‘Weave’.
But the description of a class works best when it is aware of the need to be setting neutral. A DM might want to use the Psion class for a Modern setting, and should be able to do so without getting to tangled up in the class description for the Psion.
It bothers me, the Cleric class description is way too tangled up in a specific kind of world setting. It is difficult to export this class to other kinds settings. This heavy-handed baked-in flavor is actually Hasbro corporation at work. It seeks to ‘brand’ and trademark the D&D gods, and to pressure D&D players to use them. Heh, the Cleric class is basically a corporate plant. Even the SRD5 goes out of its way to explicitly trademark the names of the D&D gods and the Outer Planes, and to pressure by means of the Cleric class and by means of the Acolyte being the only feat available, to monetize this Hasbro property. I feel this heavy handedness is misguided and will eventually backfire. A gentler approach that focuses all of this trademark property within a specific setting, such as Forgotten Realms, or perhaps especially Planescape, is more appropriate. Then players who like it can use the Planescape setting. Likewise, players who want a different kind of setting can easily use the same core gaming rules for their own creative setting. Pushing the gods on all people who ever see or play D&D is ultimately a mistake.
Anyway. I agree classes need to be open to different kinds setting assumptions. That includes how the Psion class, even if a Divine class, relates to different kinds of worlds with different kinds of explanations for how Psionics works.