Hi,
Any chance something like this could be incorporated into the livetrack feature like what Wahoo offers? What this is, is that if you already have a route loaded onto your Edge device which supports turn by turn navigation it'll show the whole route which is to be ridden laid out on the map page, rather than just a blue line across a map where you currently are as Garmin currently offers which can be slow to update at times.
Regards,
Mike.