Ok, DH, I just saw which changed you incorporated and which one's you didn't
Below are the ones you didn't and these are my arguments for their inclusion
FeatureInfo Changes:
Added comment sections naming each feature to identify them when the XML is collapsed.
Ice: Added Terrain POLAR_COAST and POLAR_OCEAN (potential usage for external map generator)
Flood Plains: Added Terrain PLAINS, MUDDY, MARSH, SALT_FLATS (in my bonus changes, allowing these expands the legal locations for several bonuses)
Forest: Removed Terrain PERMAFROST ("permafrost" to me is treeless tundra/subarctic. Really the three arctic terrains are not ideally named. IMO SNOW = arctic/ice, PERMAFROST = Tundra (ie treeless), TUNDRA =
Boreal/subarctic, which can support forest)
Ancient Forest: Removed Terrain PERMAFROST, (see above reason) and SCRUB (Ancient forest to me is thick old growth. Scrub terrain, as semi-desert, doesn't have the water table support thick forests)
Savannah: Removed Terrain BARREN (because to me Barren means no vegetation,. Also bonus changes allow barren as a legal plot more frequently for minerals)
Sword Grass: Removed Terrain BARREN (see above reason)
Crater: Added Terrain PERMAFROST, SNOW. (because meteors and angry volcano don't care how cold it is outside) Set bRequiresFlatLands to 1 (the only reason I do this is because the graphics look odd on hills)
Tarpit: Added Terrain SNOW (why can't oil/tar seepage happen in the arctic?)
Coral: Added Terrain POLAR_COAST, TROPICAL_COAST (potential usage for external map generator)
Peat Bog: Set bRequresFlatLAnds to 1 (Bogs form in low spots, not on top of hills, plus I'd double check the graphic on hills here too.)
Kelp: Set Commerce Yield to 0. (Kelp is mainly a food source) Added Terrain POLAR_COAST (potential usage for external map generator)
Sea Grass: Set Commerce Yield to 0. (Seaweed is mainly a food source) Added Terrain TROPICAL_COAST. (potential usage for external map generator)
Reef: Added Terrain POLAR_COAST, TROPICAL_COST (potential usage for external map generator)
Caves: Removed Terrain MUDDY (water table would flood them, thus removing their habitability and main game purpose)