I think the concern that most people have, ron, is that the compulsory possession of an identity card is but a small step away from the compulsion to carry it with one at all times.
The other things mentioned (passport, driving licence, etc.) only have to be carried for a specific purpose (and in the case of a driving licence do not have to be carried at all but only produced later on demand). If ID cards become compulsory it will be an easy matter for the State to demand they are always carried and failure to produce one could lead to incarceration (even if only for a short time). We don’t have people carted off for failing to prove who they are in the UK (unless they are suspected of a crime and the police are not sure that they are who they say they are).
Having said that, some sort of document to prove entitlement to medical treatment (accidents and emergencies excepted) would be very desirable, but once again it should need to be carried only for that purpose.
I don’t think many people like the idea of being asked “Vere are your papers?” when going about their business and it is that they fear rather than the document itself.