I sort of want world building software just as it covers things like "economy" vs. "plant life". If I end up creating a world that is basically Revolutionary America, I agree that it's not really needed. But if I'm trying to create a world from scratch (or one with significant deviations from a historical time and place), I can see it being really, really useful to have maps/locations/economies/etc. I'm pretty sure that some decent stuff exists somewhere (I had some discussions about a software package someone loved long ago...), so it's just a matter of finding it!