There is little evidence of airprox issues outside CAS in conditions you would be flying an IAP in earnest. The reality is there are few aircraft flying and thankfully most know what they are doing. Yes there is a risk, but statistically it is so small as to not be worth worrying about.
Irrationally I would far rather transponders became mandatory because I am as happy using TCAS for avoidance but I accept that the case for mandatory transponders is very weak given my earlier remarks.
At airports without class D I see so little traffic in IMC conditions that procedural seperation works just fine, and there is no evidence of which I am aware to the contrary. If the volume of traffic were to increase significantly that might change - but I dont think that is going to happen any time soon in the present economic climate.
Frankly based on the evidence I could fly around the UK OCAS in IMC for the rest of my life making a few approaches every day using a procedural service and never have an airprox, so based on that I think you are worrying about a solution to a problem that doesnt exist. All of which means that if someone wants to provide a flight following service OCAS free of charge I will still sign up.
