Quoting Heathrow Director: "Unlike the old primary radar, modern radars do not see flimsy aeroplanes too well so it is only sensible to have those aeroplanes properly equipped so that they can be seen."
So, what you're saying is that the new equipment is less able to do the job and so the "solution" is to force the flimsy aeroplanes to be kitted out with expensive equipment to overcome the shortfalls of the new radar ? H'mmm, sounds a bit like treating the symptom (GA trafic doesn't always appear on the radar) instead of the cause (inadequate radar).