I think there is far too much reliance on brochure ware in the whole debate.
The original premise OCTA was that aircraft would be able to see each other and thus we had "poor mans TCAS"
The concept of ADSB out allowing ATC to see aircraft OCTA is quaint, why would that be important if the aircraft is OCTA and there are no ATC services provided ??? Or are we heading back to full VFR reporting OCTA once ADSB comes in ????