Next up: The Judges Guild Ready Reference Sheets. The system, or rather systems, are actually geared towards modifying terrain at a subhex level (0.20 miles.) It assumes that a large-scale map (like the JG Wilderlands map) is being used. The intention is not to generate new terrain, but to generate obstacles to movement through pre-defined hexes.
The ref sheets have a wider variety of features that can be placed in a hex, but when used on the two-league hex scale, they don't produce a high enough density. For example, items added to the sample map were an islet off the coast, a mound in the central hex, a dip or depression in the hills to the southeast of the mound, ruins in the hills next to the sea, stakes set in the ground three hexes to the south, and a brook in the southwest of the map. A couple features couldn't be easily pictured, and I did not try out the hydrographic features table to plot out the course of the brook.
I did not use every table available; there are very detailed tables to describe the ruins, for example.
Pros: Very detailed, and details are logically linked to hex type. Includes open sea as a terrain type.
Cons: Perhaps too complicated for improv exploration. Won't generate basic terrain without tweaking. Generates very few forests, swamps, etc. Relies on GM input for many things, which may be a problem if the GM is turning to the tools for ideas. Slow.