Yes, much better documentation is needed. Many games companies (I am thinking in particular of Valve, makers of Half-Life) treat the map-makers and mod-makers as being essential to the success of their games, and provide them with proper map editing software (with documentation!) and SDKs (Software Development Kits) for mod development. These are the kind of tools we need for Shogun (and/or the sequel) Total War.

As far as texture blending is concerned, if I knew all of the textures, I may be able to write a program which can, to a certain extent, automatically blend textures. This would work a little bit like the map converter; put a map file in, get a new one out. I had kinda been planning to include such a feature in my map editor. I am thinking now that perhaps the map editor will have a phased release... that components will be released individually as they are ready (e.g. a texture blender component).

Ah if only I knew how to do 3D graphics programming