To break this down to its simplest of issues-
Before the experiment- If there was an incident in the breakdown of separation in controlled airspace, it was usually the fault of an individual...somebody didn't follow the rules or procedures.
Since the experiment- If an incident resulting in a breakdown of separation standards, in the case of a VFR in class E, noting the IFR still gets roughly the same service as was received prior to the experiment, the VFR is exempt from procedures, cause the incident but is completely protected by the regulations...all they have to say was..."I didn't think I was in conflict"
Now, if there ever is an accident in class E between a CONTROLLED IFR HVY RPT and a NON-CONTROLLED GA VFR resulting in a number of deaths???
Are you guys willing to bet the farm on this "Vanishingly small probability" incident not happening? Especially, if you continue to introduce a random event to the experiment.