The tiny amount of instrument flying in the PPL is clearly inadequate.
We used to have 4 hours of it, but it created a level of overconfidence in some pilots who would press on in conditions that they should not have been flying in. It was taken away from aeroplanes under the JAA umbrella, but given to the helicopter pilots who are allowed to fly VFR in lower visibility. The same overconfidence has appeared in some areas.
This alone indicates a little knowledge can be a dangerous thing, if you half train people to do any job, some will think they can do the whole job. And what is to stop them?