Originally posted by Blade!
Though I am not really a fan of "Call to Power", I think they handled the trading of goods in an interesting manner. The computer would generate the path based on quickest possible route, and these trade routes could be seen (perhaps on our rather bland economic map). Then, like in CTP, we could choose to break these trade routes by occuping the area they go through. The nice thing about EU is that resources are everywhere, so a proper blockade would be hard to acheive as you would have to have ships or armies surrounding your opponent... otherwise their friends and other neighbors could benefit from the revenue taxed on alternate routes. This would also make Trade Embargos more effective, especially if goods from your country, or passing through your country could not get to them... their supply would go down, increasing the costs for them! cool! 
It was also a gay idea that has no business anywhere around EU.
In reality to cities trade between eachother when you're controlling a whole nation? No, it would seem more logical to have macroecnomics, trading between whole nations. No if we have trade routes bewteen entire nations, I would agree, but between single provinces would complicate the game too much.
As far as the Navy goes, I agree that it might be a good idea that you have a merchant fleet, it was vitally important to nations like Portugal, and even the Netherlands.
However, I think maybe you should have the option to contribute to your trade by diverting money from the budget.
Maybe even have another research category dedicated to trade technology.
