MC Shudde M'ell
A weakness is sort of possible, but again you'd need to have it on an unusually strong Investigator to make them attractive or people would just play someone else.
I think Daisy is an excellent example of almost exactly this Weakness, and her Tote Bag as a counter to it. I see no reason something similar wouldn't work for Arcane slots.
Now I'm thinking Dexter Drake should have Prestidigitation, an Arcane Spell he must equip when he draws it, that shows him pulling a rabbit from a hat.