An improved inventory system.
Inventory of sims tends to get rather messy, and I kind of would like to see it being similar as many RPG's.
First of all: Equipment screen added. footwear, socks, underwear, lowerbody wear, undershirt, overshirt, jacket, neck, wrists, hands, head and belt could be the available slots.
Through this system, work clothing could function so much better. Working in a lab could simply change the jacket to a lab coat and leave all other stuff like you equipped it. Same for supermarkets and such that would just require a shirt or such to be worn from the company.
Underwear could not be removed, just replaced. Mods could change it but to keep the rating as it is and americans being prude like that, it could be handled that way.
Under the equipment screen, would be the inventory screen. I'd like to see this divided into sub categories, placing related items together.
Sub categories could be: Equippable items, ingredients, consumables, useable items and miscelanious.