Agree with HM that ICAO Standards fall short in some areas but in the Milan example I think the ICAO Standard is the best solution.
Also agree that a proactive approach to safety is needed but it's important that the solutions that may be found when being pro-active are not misleading or able to be confused with what is done elsewhere in the world. Imagine if, for example, Milan went through some thought process that lead them to make a positive decision to use the CAT II/III sign (perhaps without even asking pilots whether this is a good idea).
Pro-active yes, but ICAO whenever possible.