Having decided that this setting is going to have a focus on the psionic, i now have to consider what role, if any, magic will play in this new world. I has actually been harder than i thought, but i am leaning towards a particular solution. In saying that, another better solution may present itself that i will utilise instead.
Divine magic still has a place in the world. Even though the gods have been abandoned, they still exist as echoes of their former power, and can still grant power to their followers. The drawback for divine casters is that people react with fear and loathing when it comes to divine power from a deific source. Druids are a more complicated issue, but we will deal with that in the class discussions.
Arcane magic was very much the harder to work out here. At first I imagined a setting with a few remaining arcane practitioners, but I realised without a concrete mechanical reason, I just couldn't imagine how psionics would have gained such dominance.
So I toyed with a drawback. The Scarred Lands setting dealt with it by having arcane magic generate intense body heat, enough to make wearing heavy clothes untenable whilst spellcasting and causing concentration checks. Though that seemed interesting, the setting didn't have an alternative, and it still wasn't enough to turn people away from magic in my mind.
The next idea was Wild Magic, adding seemingly random effects on certain spells or abilities. However, I have quickly realised how much tinkering that would take, as well as how much it could slow down play to add in chaotic effects via tables and die rolls.
The solution is clearly to remove Arcane magic entirely. This obviously removed Wizard, Bard, Witch, Magus and Sorcerer. It also has repercussions on other classes, but ones that I am willing to spend the time to have fixed.
If you have any suggestions of your own as to how to deal with arcane magic in this new setting, feel free to leave a comment below.