Looking at the exsisting standards in Europe there seem to be a number of major problems that are FAR more fundemental than the colour of 3-phase cable or ot the size and shape of electrical wall boxes.
1) Lightfittings
It simply should not be possible to touch a live terminal in a lamp / light fitting.
Neither the Bayonett nor the Edison system should be acceptable they both have a pair of open live terminals that are almost designed to insert your finger(s) into. There MUST be a more sensible way of connecting a bulb!!!!
2) There are way too many varieties of Europlug based connection.
Personally i think despite the fact that they are universally accepted and very common CENELEC should do something to produce a completely new standard that wipes out the various 2 pin arrangements in europe, many of which aren't exactly safe.
Grounded appliences are regularly plugged into non-grounded outlets (despite regulations) in France, Spain, Portugal, Italy (have no experience of elsewhere).
People fit under-rated 2-pin plugs to large appliences in France to make them fit into a "bedroom" socket too.
and on another point with the advent of so many plug-in transformers (especially for mobile phones etc) many european sockets are incapable of holding the weight of a transformer..
Try plugging one into an italian flush outlet or a french non-grounded outlet. Even Schuko (or French) grounded sockets are very poor at holding a 2-pin transformer plug. They regularly just fall out onto the floor (something i've never seen happen in the UK or Ireland with BS1363)
Some sockets are shuttered, some arn't, some are fused, some arn't. They're all protected by various different combinations of circuit breaker/RCDs and no one seems to be sure just how well protected an applience is (including UK/Ireland)
I think it's pretty fundemental that a socket system should be polarised too. Schuko isn't, the french system is (but only for earthed appliences), italian system isn't etc..
Ideally a new standard should be superior and wipe out the exsisting systems in the same way that BS1363 replaced a wide range of aging and generally unsafe BS546 (and other) systems used in the UK and Ireland. (I'm not mentioning ring circuits!, they're another issue!)
We must be able to come up with something that is fundementally safe, easy to use and that everyone can agree on as a phased-in new standard.
All you'd have to do is make plenty of adaptors available in the interim period. Perhaps like the European-UK adaptors that are actually physically fitted to the europlug (it sits inside a closed adaptor). I mean in Ireland / UK the change to BS1363 took a few decades but it has generally happened very smoothly. The change of plug/socket also highlighted how old some installations were and encouraged owners to upgrade. I've seen many French farmhouses working away happily on 1930's and 1940's wiring and fittings, in the UK / Ireland that would be immediately obvious and inconvienient due to the incompatability with modern fittings.
When the EU expands we'll also be taking in a load of systems based around old soviet standards, earthed, non-earthed, scucko and other.. it would make a lot of sense to start to move to make all of these systems standardised and safer!!
Appliences could ship with the new plugs and all new installations could start using them in many cases all that would be necessary is a simple change of wallplate, in others a full rewire (e.g. UK ring systems would be a little tough to tackle unless the new system was to include plug-top fusing, which wouldn't be unreasonable simply to satisfy UK, Ireland, Cyprus (and all the other countries that might have to switch along with the European users of BS1363 .. HK, Singapore etc potentially up to 100 million people!!!!) It's not like it's the Danish standard or something (no offence denmark! but it has a signifigant user-base)
