They best way to fix this was always the same: Caster staffs, one handed weapon with 1d4 base dice, and some flavor text about being light weight and less balanced for combat and more suitable for casting spells. Use the scroll animation for attacking so it even looks unwieldy.
Just going to ignore people who don't get why caster staffs need to be treated differently than a melee Two hander (hint a Melee Two handed weapon actually gains a benefit that compensates for only having half the affixes of two weapons or weapon+ shield, it gets 1.5 damage mod and has higher base dice than one handed weapons, a caster Two handed weapon however gives NO benefit and costs you at least a red slot a spell power and a lore, probably it costs you more, now scoot off to wiki and find out stuff geez)