I do think that if passing the test means people still aren't comfortable driving at night, on motorways, or in the rain, then the test should be changed. We all need to be able to cope with whatever the road throws at us, and any driver could find themselves driving in the rain, or frost/ice, or in the dark, without having planned to (e.g. a very bad traffic jam that left people completing a journey hours later than expected), so we should be able to cope with those situations.
If people choose not to use motorways and to use other routes that's no skin off my nose, it's their choice, but if people choose not to drive in the rain and are then caught out in the rain or driving in the dark and are subsequently a danger to other road users then that could affect other people.
I don't think motorways should be part of the test in that some people live a long way from a motorway, but I do think you should have to undergo some kind of training/test on a motorway before you're allowed to use them. I also think there should be a 'winter driving' element that even if it can't be tested at all times of year, the student should be expected to answer questions about stopping distances in the snow, how to hill start in the snow, generally how to drive in the snow etc. as the people you see causing accidents by simply being clueless about winter driving are a menace.
After I passed my test my Mum made me go out driving at night, in the rain, eventually in winter conditions, and on the motorway, as she said (quite rightly) that the time to do this was when you have a choice about it, not when there is some kind of emergency and you have to (and are perhaps already distressed or distracted by the emergency).
D