There are a lot of useless things to pick up in the game. Plants, tools, objects like bottle, retort, etc.
Rather than being useless why not develop crafting?
Characters could learn from books, with scrolls, or by talking to craftsmen, consulting private or public libraries or hidden ones. Once the knowledge and materials are acquired, the characters could make, repair or improve all sorts of things. Weapons, potions, traps, ...
Maybe even provide crafting services to NPCs and earn some gold (or secrets)
We can imagine setting up production lines (Coal + iron + forge + tool + know-how = blacksmith work)
Also some actions could be refined. To go down the hole in the chapel, you need a rope. To climb a cliff, you need a rope and a grappling hook.
I'm sure Astarion would have a lot of fun making his own poisons since he's walking around in the sun and can find a lot of plants
