I've often thought that you have to do, say, 6 months on a bike, then 6 months on a 50cc, then 6 months on a 125cc then either go for a big m/bike or car license and then HGV. If you lose your license in one class you got back "down a class" for a year before re-applying. Also might reinforce the idea that driving is a privelige earned, not a right.
Of course, completely unworkable, but might give everyone on the road some empathy with everyone else.