The Cleric's never sat well with me as a class in D&D. Unlike the other three mainline classes, I can't really see how the archetype fits in the genre. Roguelike, anti-heroic adventurers make sense as mercenary warriors, cheerful thieves, and power-hungry wizards, and I can point to plenty of examples of fictional heroes that these classes emulate. But the full-armoured priest of a pagan god, spewing miracles like they were cotton candy? Receiving blessings and communications from their deific master like bonuses and memoes from upper management? All the priestly archetypes I can think of in fiction have much less magical firepower at their fingertips.
Yet in stripping out the class, I definitely feel like there's a gap that should be filled. The Mystic class I've elaborated here started out life the Spiritualist class, inspired by the mediums, psychics, and fortune tellers of gothic fiction. It's a class that derives power from their connection with the spirit world, but not through the same relationship that a priest has with their gods. Along the way, I was strongly inspired by John Harper's WoD wizards; I strongly considered making spirit-binding the default system of magic in my Daojin City Blues game, but decided it made a better match for the Mystic class.PDF Playbook for levels 2-5