See this image: http://imgur.com/a/xmNJV
Any ships trained in any harbor of the 'green area' of Littlefield, can access very limited section of the region (id estimate no more than ~20%), whereas any ships trained outside the 'green area' can access all the reminder of the map, which seems quite a disadvantage - suppose there are players A, B and C who all started at the same day - why can A and B reinforce or attack each other with ships, but C is completely locked out from it?
Maybe the world map generator could use a tweak - on this occasion, there is just a 2-cells wide landmass (see the blue bold zigzag in the middle of the map), which disables naval units inside 'green area' accessing the rest of the map... - perhaps there could be a river (or canal, if u wish) there. For naval warfare and seatrades to be smoother, there could be even more rivers in the center of the region (see red zigzags in the middle), but that is not as critical, altho it would be nice to have a shorter naval trip than 500+ cells to a town thats actually just 10 cells away.
Not sure how the world map in final release is supposed to look like, but the same problem could arise quite often, so perhaps connections with other regions (see blue zigzags on the edges) could use intersecting rivers as well.