You would think that perhaps they could modify the design of the well so that it is somehow 'filled' when the wheels are down (be it an inflatable bladder, a flap, plunger - it could even be a cheap disposable system that is changed per flight) . Another idea may be to put a simple sensor in the well to detect the presence of a person or object (microswitches, PIR, strain gauges).
It's a terrible sad event, and the more that can be done to prevent it would be welcomed.