Yeah, owning a shop, becoming a merchant is something that I always liked in some rpgs. It would be nice to sell your loot and displayed them in your shop. Ask once in awhile a buyer about fetching an item that you need, while the buyer takes xxx amount of time until he comes back with the item/s for a reward.
Also, have once in awhile, the "tax" collector to pick up their dues from your business, and also, in rare occasions, bandits/thieves breaking into your shop to steal some loot, if you're there you can kill them, if you're not, you will lose some items. If you have employees and you're absent, you'll be sent a message that your employees were able/unable to stop the theft. If one employee dies, than of course, you'll need to hire another one. All these mechanics will serve to make your business not too "overpowered".