I figured it out what I don't like about the roads: for example, on Ancient Mallorea, the terrain is a bit dull, meaning that you only have the roads and some rivers, but nothing in between. I know it is close to the sea, so maybe you don't want tress and/or mountains there, but it looks a bit too empty.
Again, I really love this style of mapping, the forest style is great amd the "glassy" look of the water on the coasts and near the islands is just wicked, very realistic.