"What I would love to see is: Given two points on the map - what is the most common path between them based on multi-path tracks of others..." Check out strava

"What I would love to see is: Given two points on the map - what is the most common path between them based on multi-path tracks of others..." Check out strava.com/routes, as others have said in the thread. It doesn't have your feature requests, but it does point to point routing based on popularity.