Yeah, the thing is that I fi wanted a world like that, I would not use class-based game for it in the first place (and I often don't.) In such a setup the classes do no seem to serve any real purpose to me, they are just arbitrarily limiting feature packages. If I use a class-based game, then I want the classes to have at least some sort of vague diegetic reality. For example, the wizards and warlocks have different rules because they are metaphysically different, and this is something that is knowable in the setting etc.