Hi Oz,
I don't know if this is an issue for others, but I have noticed that some of the BMP images for the tree, town and village hexes seem harder to see than I remember them being in previous titles. If you look at the screenshot below, the solid black arrows point to tree, town and village hexes that are easy to recognize. The green arrows indicate tree hexes which are hard to distinguish from field hexes and the red arrows point to town and village hexes that look like just the outlines of buildings.
It's mostly an aesthetics thing; though distinguishing trees from fields can slightly affect gameplay due to differences the terrain protection and line of site.
Best,
Bill