FMC Basic: Experts & Arcane Foci
Niosis and I were talking about the expert class in FMC Basic, as well as the one that appears in Lamentations of the Flame Princess or the more general (yet specific, lol) thief class. Here's kind of my take: they are the structural analogue of clerics from the 74 game, being able to use magic weapons or cast spells, and also being able to improve at combat or magic in their own particular way.
Something more interesting: if fighters specialize at the combat subsystem and mages specialize at the magic subsystem, then I think of experts as specializing in the worker-placement subsystem. This is something thieves sort of accomplish, as I've talked about before, but by having their own weird mismatch of dice rolls executed separately (and on an individual basis) from the existing worker placement game.
Finally, I think that experts could also just as well be the classless class in FMC Basic. Like I said, they can use the items associated with fighters and mages, but just don't have the crazy powers associated with them. There's just one issue in that scrolls aren't "renewable"; they always dissipate upon use.
How about another kind of treasure: an arcane focus? It has 1-5 arcane energy, letting you cast spells without spending scrolls or even cast the abstract fireball/lightning I have going on (inspired by maleficence, but a little different). This gives mages a little more to work with—to the extent that I would give them less energy—and allows experts to act more like mages should they so wish.
The focus probably serves as a simple weapon, just 1d6 damage.