"The idea of moving all your caravans through one city has a very limited effect. A city will only support 3 trade routs. If one city sends 50 caravans, each caravan will produce the one-time payment of gold, but only three will establish a permanent trade route that renders trade arrows in the city screen. However, if after the three routes are established a more prosperous one is made, the worst of the three will be dropped in favour of the new, more valuable one, so there is a possible advantage for sending more than three caravans from the same city."
Actually, I took the "send caravans to capital" strategy to mean that these caravans originate in the other cities, and you send them from these different cities TO your capital, not the other way around. That way, those satellite cities ALL get a big bonus from your capital (or SSC, whatever's your biggest trade-arrow city), but your capital only picks the top three among them for itself....
In my last full game, from each of my cities I sent one caravan to my SSC (different from my capital, but it was the trade giant), one to a large foreign city, and one directly related to demand (but on another continent if possible).... And that worked out pretty well. Sending them to faraway small cities in your empire isn't all that bad, IF you expect that city to grow very big in time as far as number of trade arrows (the value of the route will thus increase as more trade squares get used by that city). And watch when new commodities pop up in a city, like uranium or dye--you can replace a lame route with those late in the game, and get a big payout to boot....
As for the SSC always picking the BEST three, I have to beg to differ. On many occasions I sent caravans to my SSC, and saw them replace a 16-arrow route with a 13- or 14-arrow one, and overall trade went down--but not too badly. The next one could make it go back up again, too.... Anyone ever observed this phenomena? It DOES happen--I'm trying to figure out how to predict whether it will or not. Anyone?
