Perhaps someone has thought of this before but I didn't see any other posts. After I made my post about deforestation in the congress forum, I was wondering if the game code couldn't be changed to make it so rather than the world changing into grasslands->moors->heaths following deforestation, it instead would change from grassland to mudflats. (Or perhaps grassland->moor->mudflat).
This way, there would be a serious consequences to leaving huge areas of the world deforested. No animal spawns of any kind, no roots or nettles. All one would need to do is make it so that no clay can be found on these spawned mudflats and it would motivate an interesting environmental movement. "Progress is progress, and progress must grow!" vs "Progress progresses to fast!"
Besides, I can't be the only one who wants to see more aspects of the effect of industrialization on the world. I personally love the idea of being given this nice, lush world, and being able to completely ruin and despoil it if we are not careful. It adds more realism, and possible conflict over resources.
(While we're at it, perhaps water pollution from kilns, smelters, and tanning beds being put too close to water sources? Makes it unpotable and stops fish and mussel spawns.)