I'm not quite as pessimistic, indeed I think AP2 sees better rearward in such a scenario because it has a far rear fisheye. (It has no nose fisheye so two vans/wagons next to a Model S could block it's front view to the sides.) In the rear the biggest vulnerability are the elements. In good weather I think it can probably see enough in faster moving traffic too... Still, corner radars in all four corners and a nose fisheye would certainly have helped.