I haven't been working on any maps recently because I wanted to put it aside temporarily to give myself time to think. In general most RPG maps are lacking in actual usefulness. I'm not just talking about wilderness or hex maps, but also dungeon and cave maps. The big issue with most maps published for RPGs, I guess this includes fan-made maps too, is that the DM has to constantly flip between the actual map and the descriptions of what is on the map. There are almost no maps that can just be referenced during the game without looking in a module for more detail once a group reaches a certain location. Every other type of map(navigational, Choropleth, dot density, political, etc) doesn't have this problem; Each map serves a purpose and everything you to know is on the map(or at least the same poster). I don't mean to say that those detailed descriptions shouldn't exist, but rather that the map should have some way of symbolizing that detail to remind the DM what they previously read in the module.
So how to make a map for an RPG with optimized usefulness for the DM?
I'm not really sure. If you can't tell by the subject of my senior thesis, I think a huge part of it is the interactivity made available by modern web maps. Yet that's not the end all, be all to the perfect rpg map. This really just allows easier access to the data, it doesn't resolve the underlying issue: PRESENTATION. How to present that data in a visual form so the map reader instantly knows what they are looking at and doesn't have to go hunting for the exact details of that location?
One element I am dedicated to is the Hex grid. It is extremely useful for quickly measuring distance. Though the hexes don't have to be filled with a symbol like in most of the maps for Mystara; there can just be an overlying grid to show scale and distance. For every other useful thing a DM might want from a map, I'm just not sure what's best. I have some ideas, but some of those depend on a hex map, and some depend on not having hexes, so yeah . . .