I think it would be neat to haev an overall player economic statistics chart that recorded all the money you had spent and earned from traders, players, ect. Also to see how you were balancing out in your weekly spending and the overall money you had gained and lossed over your entire play time.
They had something like this in The Sims Online and it was a really neat feature. I'm sure economicly minded players would really enjoy this.
Player Economic Statistics
Sagius Truthbarron