I'm not sure but I think SDZ is referring to the map that is actually in use, perhaps he wants to use a different map within WOD, not the one that the Watch uses. Probably something like the ability to use different maps with a Garmin, but I don't think Apple allows other maps to be installed.
WorkOutDoors only allows the OpenStreetMap map that it currently shows. There is no way to use other maps. However the next version will allow you to customise the colour scheme used by the map, and also to have some control over the features that are shown on the map.