Map release shouldn't have anything to do with medal reveals. My guess is that the map has been final for quite a bit, and RD coordinated with parks ops to determine what areas would be available well in advance. At this point they should be planning for the course certification, I think that usually happens late this month or maybe early November.
Really worth noting: that weird map reveal last year happened alongside the announcement that the start time would be half an hour earlier. THAT was way more important to get out there as early as possible, I think they figured that if they paired it with an announcement about how there would be more park time in MK that would blunt the impact of the early start. Not only did that not really work, it was pretty apparent that a lot of the change was due to Epcot not wanting to deal with marathon athletes during park hours. I'm not expecting an early map reveal again this time.