The current restore feature isn't really very useful. I would prefer it if:
1. Instead of restoring to the original state, it flattens the ground in the same level as the builder (this creates problems with aircraft builders, though...)
2. A second feature enabled that instead of raising the ground lowers it, so that you can put builders in work making a canal... or a moat. =)
Number one would make more sense, since then you could flatten out hilly areas, and make bridges, while number 2 is useful for boats and to hinder troops (I know you can blow the ground up for a similar result, but it isn't very precise or effective).