I think my main goal is to make it *easy* for everyone, not necessarily simple. If I go simple on my end, it'll make things a lot harder for everyone else. My goal is to put a lot of work into the behind-the-scenes stuff and create a complex system that doesn't seem complex to the user and that allows the user to easily manage their lists.
It will also allow for fair trading. So, Rick, you won't have to worry about people 'getting more than their fair share' of goods because everything will be judged as fair on a per-trade basis.
It's the most consistent means of making sure that people don't overdraw their 'take' of the goods. Traders could always 'throw in a little extra' if they want to be generous to particular people, but that's at the discretion of the providing trader, not the trader that's 'taking'.