Yes, it sounds awesome, I don't know how much freedom it will give you, it would be great if you could edit what stores sell, but I'd be happy with just terrain modification and a lot creation tool.
Either way, it's got a lot of potential. How about...
An NWO disastopia. Police and Military stations all around, with apartment style living areas. Fences, moats and guard towers surround the border, to ensure nobody gets in, nobody gets out.(come to think of it, I could put some zombies/mummies on the outside, that would be awesome). No personal food reserves allowed, residents must come to the central civillian order station to receive medical attention and rations. To top it off, parents couldn't keep their own kids, they would all be sent to my nursery where the strongest will be sent to special military nurseries where they will learn to be cold, heartless machines of war!
HAHAHAHA! I'm soo evil!!!
Yeah, I can't wait for this editor.