Haven’t played it, but I did take the step of buying the game, so I’ll do something Microscope-y at some point (I hope. Despite all my best intentions, I’ve never been able to do anything with The Riddle of Steel, so maybe nothing will happen with this, either.)
A number of the reviews have talked about the world-building aspects of Microscope. Reviewers who generally like this kind of thing seem to like Microscope. (Some new reviews and discussion are at Story Games.
I had a conversation with Thor about the idea of incorporating some kind of mapping in with the history. The short of it: he talked me out of it (and for some good reasons). Much of it comes down to managing the technical problem of keeping maps.
We’ve used historical volumes as references for games before, and we’re well familiar with the kind of book that has 20 different maps of the same area showing the ebb and flow of borders or migrations or the like over time.
But since the game can move back and forth in time, if it is late in the game when it is suddenly now established that there is a range of Mountains out in the Western Plains, then there’s a problem. Now you have to add a feature to all the maps, since those are going to be timeless. But what about a pass through those mountains that was discovered only many years after the mountains were first discovered? What about a railroad that was now cut through? And when you get to the case of a small trading post that was set up a few miles away from an outpost fort that later came to be an important regional center before the wells dried up and it faded back to being little more than a ghost town, then you have your work cut out for you. It’s not impossible, but it’s awkward and unappealing.