This may have been mentioned elsewhere, but searching is difficult.
How about when pinning a location of a new waypoint, the map shown is the duplicates map for reviewing? That way PoGo players can see what waypoints already exist before cluttering the backlog with duplicates, and Ingress players could potentially see duplicates themselves in case a location is a bit off and you don't see it, as well as being able to eyeball if it's too close to an existing portal or not from the overhead view.
What does everyone else think? Good idea? Bad idea?