I haven't seen anything about this yet, but it seems pretty important to me. Terrain improvements in civ3 are done by workers. Controlling 50+ workers is very time consuming and irratating. The auto worker features never seem to work properly either. I would much rather have a PW, public works, system like CTP for terrain improvements than a workers system in civ4.
Post your ideas on terrain improvements here.
Post your ideas on terrain improvements here.