The current Mission Waypoints editor shows a drop-down selection of waypoint type, which includes Fly over points and turning points. So I'm guessing this is a subject that is in the works. This is my contribution toward further development.
Placing waypoints on the map produces an odd maneuvering mechanic involving a course correction that looks like so:
Here's the math necessary to calculate the turning point, given plane's speed and the angle of the turn:
My Wish: Press a button in the waypoints editor that replaces one waypoint with two turning point waypoints into the flight plan
