Let's remember the psionic is not only the class but also the monsters. Some alien monsters are better, or more Lovecraftian, but they use psionic powers instead classic magic.
I wonder something the reimagination of the wilder class like a psionic version of the barbarian, more about to relief the within rage. Something like a freak from Dandadan with middle range.
I imagine the psion's philosophy like a path of self-enlightenment to improve her own within spark of divinity. If the wizards wants to use the magic in the same way a windmill is built to use the wind, but the psionic mysthic wants to be the wind. That is the reason because clerics and paladins dislike or distrust the psionic ardents, because these don't want to serve loyalty to the supreme powers but to "recover the lost divinity".
WotC could publish a no-psionic handbook about psionic PC species and monsters, or a rewritten setting where the psionic powers, or creatures, altered the timeline, for example Krynn space being invaded or visited by gem dragons during the age of despair.
* The brainstealer dragon is a psionic monsters, isn't it?