Multiple melee weapons.

I cannot say for sure, but going by what people were able to do with modding with Dragon Age: Inquisition I doubt it since the majority of mods in Inquisition would change variables, but very little else. The reason why I think it might not be possible with Andromeda to have a mod to equip multiple melee weapons is that the game treats melee weapons differently then ranged weapons when crafting for it adds modifiers as if they were a piece of armor and not a weapon.