I would like to be able to define the route from one plane to another. The overall value of the route should be calcuated at the shortest distance, but if I am able to make my route go around the influence of an enemy, so I can actually benefit from the trade route, that would be great. It really sucks if you are in a corner and you are at war with your neighbor and the trade route you so carefully established by going around the enemy is worthless because the AI decided that the best route is through the middle of the enemy.
Better yet, trade routes should AUTOMATICALLY go around enemy territory. If and when you stop war with someone, the trade route can then go streight through their terrirtory again.
Bring on the intellegent trade routes!!!