As a relatively new ATM user (2 years) we frequently have staff discussions about what it can and cannot be used for. The classic scenario is the one where two aircraft are seen in direct conflict in class G airspace, one is known to you (but obviously not identified in true radar terms) and the other is not. The CAA line is that you can say nothing to alert your known aircraft.
What I want to know is what happens in the resulting coroners court when you are questioned as to why you observed a dangerous situation and did nothing to resolve it.
Air safety could be greatly improved by an ATM assisted FIS, but not providing radar derived avoiding action as that should remain the domain of APS rated controllers (whether on ADI duties or not).
ATM has come a long way from the old DFTI and its abilities should be used to enhance safety.