On the hand shuffling, there is method in the madness, it saves crossing the arms and getting into difficulty whilst learning (really, I have seen a learner get their arms "stuck" and run wide on a corner.
On vehicles with heavy steering/off road it gives a much better grip on the wheel than palming it round. At legal speeds there is plenty time to use the 10 to 2 technique, if you are racing a whole different set of requirements apply ( ;-) ) Finally, every so often I see someone palming a wheel round slip and have a "moment"...
At work I periodically have to supervise basic highway code tests on qualified and often "professional" drivers. The general lack of knowledge is frankly appalling. I really believe there should be a system, such as say an online basic highway code test, which should be completed annually to maintain the validity of a driving license, fail or fail to complete and licence invalid until you complete a full fresh theory test to revalidate the licence.
Also *everyone*, whether driver, motorcyclist or cyclist needs a good grasp of the Highway code if they are not to risk hypocrisy when criticising other road users imho.
Lastly, as to what was drummed in during driver training, my old man always told me that passing the test meant that I had reached the *minimum* standard required to be allowed to continue learning to drive unsupervised, a "driver" I was not yet!