It would make a lot of sense to abandon both of those systems. They're fine in a totally isolated environment where people don't travel and, particularly in the case of Denmark (a small country within the EU) it must be very difficult to avoid appliances shipping with Schuko plugs.
If there's no advantage to the systems they shouldn't be kept.
As for the Italian system. It could be phased out rather easily by simply replacing the wide-spaced 16A italian plugs with schuko and introducing an Italian version of the schuko socket outlet that incorporates a receptical for the italian ground pin on the 10A plugs.
As for the UK and Ireland I'd advocate introducing a fused schuko socket outlet that fits BS plates. I'm sure there must be a practical work-around to allow the UK to keep its ring circuits yet use a more compatable plug / socket system.
