1st- the trade list could really use a filter at the top, default for both the buy and sell columns could be "show all", but a scroll menu of individual items at the top of each column would be a huge improvement. For example, if I want to buy some bronze swords I should be able to set the offers column to show only offers of swords. Likewise, if I want to sell some tools, I should be able to set the cost column to only tools. If I want to see who is offering the best exchange rate I should also be able to set both columns, eg- show only the swords for tools trades. Forge of Empires uses a system along these lines, and it makes trading much easier.
2nd- It would be nice to have a list of all active trades, with the option of cancelling any given offer to buy.