This isn't guarenteed, this is just me writing down my thoughts on the idea.
Instead of a trading system, maybe a Player Hosted Auction system would work better. Players could choose what item to auction (could restrict certain items such as items you buy in a store players couldn't buy an item and auction it for a higher price to unaware players), how long to auction it for, and maybe a minimum bid. Players could auction their own items and reduce spam for staff to host auctions all the time, and fix the timezone problem of auctions.
To prevent players going in a low populated room and giving items to friends for a low price/not making much money on an item, if it doesn't reach a certain amount of money, the player gets their item back. Maybe limit the amount of auctions a player can host a day so players don't get rich quick and ruin the economy.
Anyways, this is just me writing down my thoughts on this concept. Thoughts on this?