The caravan system is interesting, but it's clearly broken right now in anything over a standard sized map. this needs to be fixed. A single trade route per specific techs isn't going to work - you need to be able to scale the number/range of trade routes with the size of your empire.
This really needs to be re-worked soon, it's such a glaring problem that I'm amazed it made it into the release this way.
This really needs to be re-worked soon, it's such a glaring problem that I'm amazed it made it into the release this way.