The problem with that is, since buildings need to be built on bulldozed terrain, that means bulldozed terrain will be created/destroyed pretty much every turn anyways, so you'd still end up having to recalculate routes just as frequently. This could be mitigated somewhat by only checking if bulldozed tiles making up the route were destroyed/built over, but then there's still the issue of figuring out if a newly bulldozed tile has opened up a faster route. Obviously, you and I can tell pretty easily that a newly bulldozed tile on the other side of the planet won't make a faster route than the one that already exists, but route calculation would still need to check it anyways, unless there was some other process filtering out tiles that were too far away to be part of a faster route, but that in itself could be pretty complicated to write, and there's always the risk of incorrectly filtering out tiles that actually are part of the shortest route. At the risk of putting words in leeor's mouth, it might be worth coming back to this in the future, but since there's already a good enough and fast enough solution, I'm guessing it's low priority.
