I loved reading this. Perhaps my own bias towards historical references, or it was my enjoying reading something that really wanted to evoke the vision, either way this sounds like the sort of game I would definitely play. As others have mentioned, some of the specifics can be a little lacking, so it's not as useful for the dev team, but I often think there's tremendous value in setting the vision (even if it either needs an update or a companion document to get to a level for directing development).