Idea: (maybe someone is listening)
Resource site: occuring on the edge of the map called a Trade Route. It would mark a point where trade carts or ships could "connect" with the outside world.
Building: Market. Origin point of trade carts, from which they travel to a designated trade route. This building could not be built within a certain distance of its designated trade route on the map, so that you could build one right beside a route, but not send trade to that route. Reason being to make convoys necessary so that they are risky and can be raided.
Process: This wouldn't be an automatic resource generator, but rather you would purchase resources with other resources at the market, such as in AoK, but rather than recieve them automatically, the convoy would have to walk/sail the route, perhaps several trips in order to carry out the transfer. Likewise, if the trade carts/ships are destroyed enroute you lose that shipment.
What this would do: By having designated trade routes, there are definate places to raid, known to your enemy, but you would be able in theory to build these routes deep in your territory, and so make raiding them more difficult. Having the delay in the trading of resources also makes the trade carts something very important to protect, rather than just some easily replaceable unit, and it prevents a player from immediately making up for a shortfall that they should have seen coming.
I think my idea strikes a good balance between risk and ease of use. So, any thoughts? And developers willing to pay me loads of cash for my idea, or at least send me a free tee-shirt?...j/k :-) Seriously though, good idea or bad idea?