I've wondered how this is going to work for Dark Sun in particular.
I didn't play 4e at all, let alone in the DS setting, so the idea of an Athas where the rare and widely hated arcane casters have infinite spammable cantrips is going to take a while to get my head around. There's some cantrips that could pass as psionics i suppose (so long as another psionicist or caster isn't nearby and able to tell the difference). Vicious Mockery, Mold Earth, Message, Mind Sliver, Mage Hand, Friends, Blade Ward and the like could all be telepathic or telekinetic manifestations, and you could make a case for things like Poison Spray as biometabolism.
But there's just so damn many cantrips flying around in 5e. How do you in-world justify the fear and hatred of arcane spellcasters in an edition where magic is so much more common across all classes? And it's not just cantrips. I mean, stereotypically back in the 2e era the magic-hating barbarian was a very common trope, but now I'd guess more than half of the barbarian subclasses we have get some sort of quasi-magical ability along the way somewhere, from summoning flumphs to growing a tail. The mechanics of the current edition just don't support that sort of magic-suspicious world setting very well without a major rewrite.
I'd be happy, for instance, giving arcane spellcasters light armour proficiency and maybe a martial weapon or two (psionic wild talents can level the playing field in Athas too) in exchange for a hard mechanical enforcement of the preserving/defiling system (preserving is hard but sustainable, defiling is easy but ruins the world forever). But with so many spellcasters running around now (hell, even BARDS are primary spellcasters who can get 9th level slots now), and with the plethora of subclasses even of non-traditionally magic classes who get spellcasting, running a low-magic setting in 5e without major surgery to the class list is a hard thing to do.