Leave the rear view camera image on the upper part of the center display. It clearly shows the traditional "blind spots" that other cars have, but the Model S does not.
The rear view wide angle lens is so wide that it covers everything up to the point where you can see cars to the side of you in your peripheral vision without even turning your head.
NOTE: the new AP auto lane change feature cannot safely change lanes unless the driver does a visual check first. Tesla makes no claims that auto lane change can be done safely just based on the vehicle sensors without driver participation. The driver must first verify that a lane change can be made safely before initiating auto lane change!